Boulder County

Author(s): Nathan Pieplow
County Seat: Boulder
County Size: 741 square miles
Low Elevation: 4,893 ft. - St. Vrain Creek on the Weld border
High Elevation : 14,255 ft. - Longs Peak
Best Birds : Sharp-tailed Sandpiper (1975), Garganey (1992), Brambling (1983)
Checklist : Download pdf | View HTML
Introduction: Though it is usually included in discussions of the "Metro Area," the city of Boulder considers itself distinct and has bought enough open space along its south and east borders to ensure that the suburbs of Denver never envelop it. With its numerous plains reservoirs, migrant traps, and mountain parks (including the highest part of Rocky Mountain National Park), Boulder County has something to offer the birder on every day of the year. Many thanks to Bill Schmoker for his comments and revisions on the text of this page, and to Bill Kaempfer and Randy Seibert for their contributions.

Birding Locations

CU South Campus Ponds
Description - This area is owned by the University of Colorado but has not yet been built on, and so in the meantime it serves the function of open space. A couple of small ponds on the property can be attractive to waterfowl. Otherwise the whole place is mostly grassy areas with scattered second-growth trees, sometimes good for hawks and sparrows. One winter a Varied Thrush showed up in the Russian-olives on the west side of the property.
Habitat - Pond/Lake/Reservoir, Grassland/Prairie, Hedgerow/Shelterbelt
Directions - From Denver, take US 36 to Boulder, exiting onto Table Mesa Road (note: this is a tricky double exit; take the right off of US 36 and then another immediate right to get to Table Mesa). At the bottom of the entrance ramp, turn left (west) onto Table Mesa and follow it back under Foothills Parkway, past the Park'N'Ride, and over US 36. Just past the US 36 bridge, take the first left onto South Loop Drive (sign for CU South Campus).
Delorme - 40 A1
Roads of Colorado - 56 B3
Varsity Pond
Description - The pond itself, on the northwest corner of the CU-Boulder campus, isn't worth much to birders, but the surrounding trees are, especially the small thicket along the north side. This is a classic quickly-birded migrant trap. Northern Waterthrush is a decent bet here in May, and rarer birds are reported regularly.
Parking can be a problem in this area. Metered parking is available along University Avenue, just a few yards north of the pond.
Habitat - Pond/Lake/Reservoir, Lowland Riparian
Directions - Varsity Pond is just south of University Avenue and east of Broadway (CO 93) on the CU campus in Boulder. From Denver, take US 36 to Boulder and turn left onto Arapahoe Road. 1.5 miles west of US 36 (=28th Street), turn left (south) onto 17th Street, which curves right and becomes University Avenue very close to the pond, at the top of the hill.
Delorme - 30 D1
Roads of Colorado - 56 B3
Boulder Creek (downtown section)
Description - Many sections of Boulder Creek provide excellent birding year-round, but arguably the most famous part stretches about two miles from 6th Street on the west to Folsom Avenue on the east, running along the south edge of downtown Boulder and the north edge of the CU-Boulder campus. Worth a check at any time of year, this area is particularly productive during spring migration. Its birdlist is as long as your arm, with rare eastern vagrants from the elbow down.

A bike trail (the Boulder Creek Path, not to be confused with either of the South Boulder Creek Trails, q.q.v.) runs along the creek throughout this section and far beyond in both directions. In many areas, informal trails provide better access to the brush or to the creek itself. In general it is okay to bird these trails, but beware damaging the habitat and trespassing on private property.

The west end of this area, around 6th Street, has some of the more mature trees and some of the thickest underbrush, and can be excellent for migrants. As you walk east towards (and eventually under) the library, the trees and brush thin out considerably. Ironically, the area immediately adjacent to the library has produced some of the creek's most famous vagrants, including a singing male Cape May Warbler that stayed for several days in May 2004. Do not give this section short shrift!

East of the library the creekpath crosses under Broadway and then runs just south of the Boulder High School campus. This section does not tend to be very birdy, but west of 17th Street the path starts to get more productive. Between 17th and Folsom, three footbridges cross the creek to campus. Between the western two footbridges, on the south side of the creek, is a terrific small wooded area crisscrossed by footpaths. This may be the best-known migrant trap in Boulder; Eastern Screech-Owl is resident. As the patch lies at the foot of the hill topped by the CU Recreation Center, it is often simply referred to as "below the Rec Center." Good habitat extends east nearly to Folsom.

Parking can be a problem in this area of Boulder. Most birders choose to park in the public library lot, since parking here is free before 9:00 AM. After 9:00 AM you must buy a parking pass. If school is not in session, the Boulder High School parking lot can be a good place to park. Some free curbside parking is available south of Arapahoe along 19th. There are also a few metered public spaces right along the creekpath in CU lot 169, on the north side of the creek and the west side of Folsom. These sites often fill, however, so be prepared to walk some distance if you're headed to the Rec Center area.
Habitat - Lowland Riparian, Stream
Directions - This section of the Boulder Creek Path runs through downtown Boulder. From Denver, take US 36 to Boulder and turn left onto Arapahoe Road. To reach the CU Folsom parking lot (169), turn left on Folsom Avenue, then turn right into the parking lot entrance road immediately before crossing Boulder Creek. Boulder High School is on the south side of Arapahoe 1.5 miles west of US 36 (=28th Street). The Boulder Public Library is on the north side of Arapahoe a quarter mile west of Broadway.
Delorme - 30 D1
Roads of Colorado - 56 B3
Gregory Canyon
Aliases - Chautauqua Park, Flagstaff Mountain, Boulder Mountain Parks
Description - If you are not a Boulder County Residents and do not have Boulder license plate, there is a $3 parking fee for Boulder Mountain Parks. This is enforced! The Gregory Canyon lot is tiny and typically full. If so, park out along the road somewhere and walk in. Please check current regulations in Boulder County.
If you follow Baseline Road in Boulder all the way west until it runs into the foothills, you will find yourself at the entrance road to Gregory Canyon, which may be the finest patch of riparian foothill habitat in the Front Range. It is one of the only places in Colorado with a native stand of Ironwood, a trademark tree of the eastern deciduous forests. Perhaps because of the familiar flora, this area seems to act as a magnet for eastern vagrants, which have included Red-shouldered Hawk, Ovenbird and Blue-winged and Prothonotary Warblers. White-eyed Vireo, Hooded and Kentucky Warblers have summered in the area, and the vireos may have fledged young! In the warmer months, Gregory Canyon is an excellent place to find specialty foothill and riparian birds like Gray Catbird, Yellow-breasted Chat, and Virginia's and MacGillivray's Warblers, all mixed with birds of drier ponderosa habitats like Western Tanager and Plumbeous Vireo, not to mention cliff-loving birds like Canyon Wren and Golden Eagle. Trails split off from the parking lot in several directions, and each of them is worth birding, particularly for the first hundred yards or so. Don't neglect the entrance road either. The draw along the lower portion of the Amphitheater Trail is worth particular attention.
Adjacent to Gregory Canyon on the south and southeast is Chautauqua Park, one of the more popular recreational areas in Boulder, with multiple trailheads. From Gregory or Chautauqua you can access the Mesa Trail (q.v.) and walk all the way south to Doudy Draw if you so desire. Chautauqua's trails offer most of the same birding opportunities as Gregory Canyon, minus the fabulous riparian stuff.
On the other side of Gregory Canyon is Flagstaff Mountain, which is where you'll end up if you follow Baseline up the hill past the entrance road to Gregory. Flagstaff Mountain Road is spectacularly steep, winding, and narrow, and it is made narrower by the crowds of masochistic bikers huffing their way uphill on the right and down on the left. Be very careful of them while driving. The various lookouts and trailheads along the road are good for scenery and for the more common Ponderosa birds. Owling from this road in spring can sometimes produce Northern Saw-whet and even Flammulated Owls, both usually heard far below you, in upper Gregory Canyon, from one of the overlooks.
URL - Gregory Canyon
Habitat - Ponderosa Forest, Foothill Shrub, Lowland Riparian, Cliff Face, Stream
Directions - From Denver, follow US 36 into Boulder, exiting at Baseline Road. Turn left (west) on Baseline and follow it west past Broadway and up the long hill. The main entrance to Chautauqua Park is on the left (south) after the top of the hill. The entrance road to Gregory Canyon is just past where Baseline curves sharply to the right and begins to climb steeply, becoming Flagstaff Mountain Road.
Delorme - 40 A1, 30 D1, 29 D7
Roads of Colorado - 56 B3
Skunk Canyon
Description - Skunk Canyon offers a very diverse environment starting with foothill shrublands and continuing on for 1.3 miles through ponderosa pines and Douglas-firs. Golden Eagles, Prairie Falcons, and Peregrine Falcons nest on the Flatirons cliffs at the head of the canyon. Summer residents include Broad-tailed Hummingbird, Scrub and Steller's Jay, Blue-gray Gnatcatcher, Gray Catbird, Virginia, Yellow-rumped, and MacGillivray's Warbler, Yellow-breasted Chat, Spotted and Green-tailed Towhee, Lazuli Bunting, and Black-headed Grosbeak. Winter residents include Downy Woodpecker, Red-breasted, Pygmy, and White-breasted Nuthatch, Townsend's Solitaire, and Dark-eyed Junco. Recent rarities include Chestnut-sided Warbler and Indigo Bunting. Thanks to Boulder Audubon for this information.
URL - Skunk Canyon
Habitat - Foothill Shrub, Ponderosa Forest
Directions - Starting at Baseline & Broadway in South Boulder head south to Dartmouth (0.8 mile). Turn right & continue 0.2 miles to Kohler. Turn left and continue on Kohler for 0.8 mile. Take a right on Deer Valley Road for one block. The trail begins where Deer Valley Road deadends at Hollyberry Lane.
Delorme - 30 D1
Roads of Colorado -
Walker Ranch Open Space
Aliases - Meyers Homestead trail, Gross Reservoir State Wildlife Area
Description - This was the site of the Walker Ranch Fire in 2000, which burned much of the park. Three-toed Woodpeckers have taken up residence in the resulting burn, but they can be very difficult to find, and both Hairy and Downy Woodpeckers are far more common. In some years, winter trips to the burn have also produced Bohemian Waxwing, White-winged Crossbill, Northern Pygmy-Owl and Eastern Bluebird, though none of these is to be expected. More likely are mixed flocks of chickadees, nuthatches, kinglets, creepers, juncos, robins and solitaires. Any of Colorado's regular raptors might fly over.
The upper parts of the Meyers Homestead trail, starting about a mile from the parking lot, have been productive on recent spring and early summer nights for Common Poorwill and Flammulated Owl. The poorwills are rather common and may be almost anywhere in the area, but typically call mostly during a brief period right around dusk, and only sporadically thereafter. The Flammulated Owls are on the steep wooded hillside across the stream from the trail, starting about a mile from the parking lot and continuing until the trail bends away from the stream, about a mile later. Unfortunately, water and airplane noise can make owling difficult, and the owls are silent some nights even in peak season. Northern Saw-whet and Northern Pygmy-Owls are a possibility along this trail as well, as is Dusky Grouse during the day.
Just down the road from the Walker Ranch trailheads, and contiguous with part of the burn, is the Gross Reservoir State Wildlife Area. I have never seen a SINGLE waterbird on this reservoir, but you could get lucky. The surrounding forests have the same potential as those of Walker Ranch.
URL - Walker Ranch Open Space
Habitat - Burn Area, Ponderosa Forest, Mountain Meadow, Stream, Aspen Grove
Directions - There are two trailheads in the Walker Ranch Open Space. The Meyers Homestead trail leaves from the trailhead on the west side of Rd 77, about 1.5 miles beyond Kossler Lake if you are coming from Boulder. The other trailhead provides access to the Columbine Gulch and South Boulder Creek Trails and is accessed via the short dirt road that leaves Rd 77 at its sharp turn to the right (west) just beyond the turnoff to the other trailhead. Gross Reservoir is along Rd 77 a few miles farther west. Rd 77 is the continuation of Flagstaff Mountain Road, which itself is the continuation of Baseline Road in south Boulder.
Delorme - 39 A7
Roads of Colorado - 56 A4-B4
Betasso Preserve
Description - Well up in the foothills, this preserve provides access to extensive Ponderosa Pine and mountain meadow habitat. It is the most reliable site in the county for breeding Western Bluebird, although Mountain Bluebirds are far more numerous. Pygmy Nuthatches and other common ponderosa birds can be relied on.
URL - Betasso Preserve
Habitat - Ponderosa Forest
Directions - From Boulder, head west on Canyon Boulevard (CO 119) up Boulder Canyon towards Nederland. About five miles from Boulder, turn right (north) on Sugarloaf Road and follow it about a mile to Betasso Road. Turn right on Betasso and follow it into the preserve.
Delorme - 29 D7
Roads of Colorado - 56 B3
Caribou Ranch Open Space
Aliases - Mud Lake Open Space
Description - This relatively recent addition to the Boulder County Open Space system is one of the better properties in the county, containing a variety of montane habitats. Unfortunately it is closed from April through June to give calving elk their privacy, which makes it hard to check the riverside willows for breeding Veery and Fox Sparrow. Fox Sparrows, at least, can be found breeding at the Caribou Bog, which is outside the park. The Mud Lake Open Space may be worth a visit, although it is no substitute for Caribou Ranch.
URL - Caribou Ranch Open Space
Habitat - Ponderosa Forest, Lodgepole Forest, Mixed Conifer Forest, Mountain Meadow, Streamside Willow, Foothill Shrub
Directions - From the traffic circle in downtown Nederland, head north on CO 72. To get to the Caribou Bog, take a left at the north end of town onto CR 128 (signed for Caribou). Follow the road to its end. The bog is downhill to the north of the road, down a footpath through some trees. To get to Caribou Ranch and Mud Lake, head north from the traffic circle two miles to CR 126 and turn left (west). The entrance to Mud Lake Open Space is just down CR 126 on the left. The parking lot for Caribou Ranch is about a mile further down on the right.
Delorme - 39 A6
Roads of Colorado - 55 F3
Brainard Lake area
Aliases - Red Rock Lake, Mitchell Lake Trailhead, Long Lake Trailhead, Lake Isabelle, Blue Lake, Mount Audubon, Audubon (Mount)
Description - This is one of the premier mountain recreation sites in the county, and it is almost always crowded. The road from Ward to Brainard Lake (FR 112) is about four miles long. At about the halfway point is Red Rock Lake. In winter, the road is closed at this point and all further access must be on foot (typically, on foot with snowshoe or ski attached). In summer there is a fee station here. About two miles beyond the fee station the road splits to encircle Brainard Lake and thereafter sends spurs off to two trailheads, the Mitchell Lake and Long Lake trailheads.

The area around Brainard Lake and its subsidiary trailheads contains the best road-accessible spruce-fir habitat in the county, and the vicinity can be excellent for birds like Gray Jay, Pine Grosbeak and Three-toed Woodpecker. Boreal Owls have been found in this area too, but they are difficult to get. In spring, they usually quit singing by the time the road opens, so finding them requires a potentially dangerous nocturnal snowshoe expedition through avalanche country. Later in the season, the similar-sounding Wilson's Snipe can confound the search. The best bet is probably to search the area in fall before the snows, playing a tape and hoping for a juvenile bird to come in. Note that the farther up the road, the better the habitat. The area along the road near Red Rock Lake is Limber Pine, not spruce-fir, and therefore not very good for Boreals.

If you want the tundra birds in Boulder County and don't mind a strenuous hike, Audubon Peak is the place to go. You will have to hike a steep mile from the Mitchell Lake trailhead to treeline, but once you get there, you get to spend a long time on the tundra. This is a good hike for ptarmigan (I see them here on about half my trips) and Brown-capped Rosy-Finch. To see the finches, you will need to be high up on the mountain itself--they actually breed behind Audubon on the rocky, snowy Paiute Peak. If you don't see them on Audubon, head over towards Paiute from the peak, exercising extreme caution on the rocks. The traverse to Paiute requires real mountaineering skill, but with luck you should be able to get close enough to find some finches without having to do any actual scrambling. Keep in mind that the long distance above treeline is both a blessing and a curse. If bad weather sneaks up on you from the other side of the Continental Divide, you will have no place to hide. Keep a very close eye on the sky, and come prepared for a serious hike of a 13,000 foot peak.

You may prefer to hike to Lake Isabelle or Blue Lake, at the base of these mountains where the tundra begins. Ptarmigan are possible here, but unreliable. But pipits abound, and Rosy-Finches can sometimes be seen, especially where snow persists in cliffy areas. Be very careful up there.
Habitat - Spruce-Fir Forest, Pond/Lake/Reservoir, Streamside Willow, Krummholz, Alpine Tundra, Cliff Face
Directions - From Boulder, take Canyon Boulevard (CO 119) west from town to Nederland. At the traffic circle in Nederland, take CO 72 (the Peak-to-Peak Highway) north to the town of Ward. In Ward, turn left (west) off the Peak-to-Peak onto FR 112, which is the road to Brainard Lake.
Delorme - 30 B2
Roads of Colorado - 55 F2-F3
Prince Lakes, Erie and Thomas Reservoirs
Aliases - Erie Reservoir, Thomas Reservoir
Description - Well-known spots for gulls and occasionally geese, diving ducks or shorebirds. If you are here in the winter and see no gulls on one of these small lakes, check the other three, or perhaps the nearby Lafayette Storage Ponds. Gulls particularly like a combination of ice & open water- the lake offering the best ratio of both water phases will often be the hotspot. The flocks often move around during the day, feeding at the Erie landfill, and generally spend the night at Valmont. When numbers of gulls are high, these are prime spots for finding rarities.
Habitat - Pond/Lake/Reservoir
Directions - Prince Lake #1 is on the southeast corner of US 287 and Arapahoe Road in Lafayette. Parking is at the northeast corner (but beware of no parking zones.) Erie Reservoir is a quarter-mile north, on the other side of the Safeway store, and is best scanned from a small parking area on the east side of US 287. To get to Prince Lake #2 from Prince Lake #1, drive about a quarter mile east on Arapahoe, then turn north on 111th Street, which proceeds through the housing development to skirt the lake. The best scanning spot is where 111th bends east along the south shore. To get to Thomas from here, continue north on 111th to the T intersection with Isabelle Road and turn right, then south on 119th. Thomas Reservoir (not to be confused with the Thomas Reservoir or the Lake Thomas in Weld County, q.q.v.) is on the east side of 119th Street, about 0.5 miles south of Isabelle Road and 1.25 miles north of Arapahoe Road.
Delorme - 30 D2
Roads of Colorado - 56 C3
Lafayette Storage Ponds
Description - These ponds can be very good for winter diving ducks and have hosted all three scoters in addition to Barrow's Goldeneye. It can also be a gull stopover, as there is usually at least some open water surrounded by ice in the winter (see also Prince Lakes, Erie & Thomas Reservoirs.)
Habitat - Pond/Lake/Reservoir
Directions - The storage ponds are northwest of the town of Lafayette, on the west side of US 287 half a mile north of Isabelle Road and approximately two miles north of Arapahoe Road. US 287 is a very busy highway and pulling over on the shoulder is not recommended. Instead, pull into the short driveway/access road at the north end of the ponds and walk up to scan through the chain-link fence.
Delorme - 30 D2
Roads of Colorado - 56 C3
Bobolink Trailhead
Aliases - South Boulder Creek Trail, Centennial Trail
Description - True to its name, this is the only reliable spot for breeding Bobolink in the county, and one of very few regular breeding sites in the Metro Area. The birds do not typically arrive until at least mid-May, and they leave by the end of July. They may be in the fields to the south of Baseline and east of the trail (here called the South Boulder Creek Trail), or in the fields to the north of Baseline and to the west of the trail (here called the Centennial Trail). Also be on the lookout for grassland sparrows, and for landbirds in the trees along the creek.
If you follow the South Boulder Creek Trail south a mile and underneath US 36, you will find a breeding colony of Northern Rough-winged Swallows and some fields to the southwest which in some years have had breeding Grasshopper Sparrows. The riparian habitat continues all the way along the creek. You can also reach this spot by hiking north from the South Boulder Creek Trailhead.
URL - Bobolink Trailhead
Habitat - Grassland/Prairie, Lowland Riparian, Stream
Directions - The Bobolink Trailhead is on the south side of Baseline Road just west of Baseline Reservoir in southeast Boulder. From Foothills Parkway (CO 157) in Boulder, head east on Baseline Road approximately one mile to the trailhead, located just west of the "T" intersection with Cherryvale Road.
Delorme - 30 D1; 40 A1
Roads of Colorado - 56 B3
Baseline Reservoir
Description - Though private, this lake can be well scanned from the wide shoulder of Cherryvale Road along its southwest shore. When it has open water during the colder months, it can be a good spot to turn up waterbirds including loons, gulls and diving ducks. Occasional rarities are reported.
Habitat - Pond/Lake/Reservoir
Directions - Baseline Reservoir is in southeast Boulder. From Foothills Parkway (CO 157) in Boulder, head east on Baseline Road approximately one mile to the "T" intersection with Cherryvale Road. The best scanning spots are a half-mile south of this intersection along Cherryvale. A left turn on Cherryvale will reconnect you with eastbound Baseline Road, which jogs around the lake. You can see the lake from this part of Baseline, but there are no good places to pull over and scan. On the south side of Baseline just east of the lake is a parking lot which provides access to the open space trail that flanks the southeast shore of the lake.
Delorme - 30 D1; 40 A1
Roads of Colorado - 56 B3
Mount Sanitas
Aliases - Sanitas Valley Trail
Description - This very popular open space on the west side of Boulder has some nice habitat. The Sanitas Valley Trail heads north along a draw full of deciduous tangles that can harbor migrants. Sage Sparrow has shown up here. Farther up the slopes are open stands of Ponderosa Pine, patches of montane shrubland good for Virginia's Warbler, and rock cliffs full of Canyon Wrens.
URL - Mount Sanitas
Habitat - Ponderosa Forest, Lowland Riparian, Foothill Shrub, Cliff Face
Directions - From the corner of Broadway (CO 7) and Canyon (CO 119) in downtown Boulder, head north just outside downtown to Mapleton and turn left (west). The parking lot for Mt. Sanitas is along Mapleton a block west of 4th.
Delorme - 30 D1
Roads of Colorado - 56 B3
Rollins Pass (Boulder County section)
Description - Part of the Moffat Road, near Yankee Doodle Lake and Jenny Lake, runs north into Boulder County from Gilpin, making this the only stretch of road-accessible tundra in the county. The road is not particularly good, but should be passable in most passenger vehicles. As everywhere, even if you make your car do the work of bringing you up this far, you will still have to hike to find ptarmigan and rosy-finches!
Habitat - Alpine Tundra
Directions - From CO 119 at Rollinsville south of Nederland in Gilpin County, drive west on the Moffat Road. The rough road up the pass heads east at an extremely acute angle from the main road about two miles short of the Moffat Railroad Tunnel.
Delorme - 39 A5
Roads of Colorado - 55 F4
Stearns Lake
Description - This lake is good during the colder months for diving ducks and during migration for almost any waterbird. If the water is low, this can be one of the county's premier shorebird sites. Swallow numbers in migration are often impressive. The marshes on the west side can be good for blackbirds and sparrows. Though most birders stop at the lake itself, the trail continues over a stream to a few trees, some fields and some ponds, all part of the Carolyn Holmberg Preserve at Rock Creek Farm, which can be worth checking especially in migration.

County listers beware (or rejoice!): Broomfield's counterintuitive boundaries encompass everything to the west of the road here, including the small pond just northwest of the Stearns Lake parking lot.
Habitat - Pond/Lake/Reservoir, Marsh, Stream, Grassland/Prairie, Hedgerow/Shelterbelt
Directions - The Stearns Lake parking lot is on the east side of 104th Street one mile south of Dillon Road, northwest of Broomfield. From US 36 westbound from Denver, take CO 121 north through Broomfield, then turn left in three miles onto Dillon Road. From US 36 eastbound from Boulder, take McCaslin Boulevard north from the Superior exit and turn right onto Dillon Road at the first stoplight, less than a quarter mile from the exit.
Delorme - 40 A2
Roads of Colorado - 56 C4
Marshall Mesa
Aliases - Marshall Reservoir
Description - Just south of Boulder, this trail is much more popular with hikers than with birders, although the sparse ponderosas with some underbrush can be good for the more common foothill birds. Probably the best reason to come here is to scan Marshall Reservoir, one of the largest bodies of water in the county, and one of the least accessible. The reservoir is private, but open space land goes right up to its shores, and a short steep hike will put you in good scanning position. To get to the north shore, head up the trail from the parking lot and take a left at the first branch in the trail (signed to "Community Ditch"). This trail gains altitude and then swings back to the right and eventually joins up with the Community Ditch, a deep canal that feeds the reservoir. Follow the canal up to the reservoir to scan it. It's a pain to carry a scope up this steep half mile, but you may be glad you did.
URL - Marshall Mesa
Habitat - Pond/Lake/Reservoir, Foothill Shrub, Ponderosa Forest, Grassland/Prairie
Directions - From Boulder, take Broadway (CO 93) south out of town a few miles to its intersection with Eldorado Canyon Road (CO 170). Turn left (east) on CO 170 and follow it a short distance to a stop sign, at which you will turn right to stay on CO 170 (Marshall Drive). Follow the road about a half mile to the trailhead, on the right (south) side of the road.
Delorme - 40 A1
Roads of Colorado - 56 B4
Greenbelt Plateau Trailhead
Description - In recent years this has been one of the easiest spots to find breeding Grasshopper Sparrows in Boulder County. The birds can be found in small numbers in the grassland to the north and east of the trailhead. Vesper Sparrows are abundant.
URL - Greenbelt Plateau Trailhead
Habitat - Grassland/Prairie
Directions - This trailhead is located on the northeast corner of the junction of CO 93 and CO 128 south of Boulder. If you do not find Grasshopper Sparrows here, you might also want to check around the Flatirons Vista Trailhead, a half-mile south on the west side of CO 93.
Delorme - 40 A1
Roads of Colorado - 56 B4
Doudy Draw and the Mesa Trail
Aliases - Mesa Trail
Description - These trails, which start just across the road from one another, are two of the most popular birding spots in Boulder. Doudy Draw's main claim to fame is spring migration, although late summer regularly draws wandering Cassin's Kingbirds and Northern Mockingbirds, both rare in Boulder County. In spring, check riparian habitats for all sorts of migrant foothill birds, from towhees to Empids to tanagers, and expect good numbers of Indigo/Lazuli/hybrid buntings and maybe a vagrant eastern warbler. The first nice tangle is on the right (west) side of the trail, a quarter mile from the trailhead. Farther on, the trail crosses the creek, and the riparian habitat is excellent from that point onward for at least the next quarter mile. Upland habitats in this area are good for Say's Phoebe and the like. Bullock's Oriole and Blue Grosbeak can be expected throughout the summer.
Across the road, the riparian area right around the Mesa Trail parking lot can be counted on to deliver many of the same goodies, along with maybe a dipper if the stream is running high. Eastern Screech-Owl can be heard here sometimes after dark or just before dawn. Several trails lead up into the foothills from here, and all can be birdy. This is one of the best places in the county to come hunting for Bushtit or maybe Western Bluebird, and a couple pairs of Northern Pygmy-Owls usually nest up in the conifers--you might be able to whistle one up at any time of year. If you get up near the cliffs, keep an eye and an ear out for nesting Peregrine and Prairie Falcons in addition to Canyon Wrens and a foothill avifauna similar to that of the adjacent Chautauqua Park.
URL - Doudy Draw and the Mesa Trail
Habitat - Lowland Riparian, Stream, Foothill Shrub, Grassland/Prairie, Ponderosa Forest, Cliff Face
Directions - From Boulder, take Broadway (CO 93) south out of town a few miles to its intersection with Eldorado Canyon Road (CO 170). Turn right (west) on Eldorado Canyon Road. The parking lot for Doudy Draw is on the left (south) in about two miles, and the parking lot for the Mesa Trail is directly opposite it on the right (north).
Delorme - 40 A1
Roads of Colorado - 56 B4
Eldorado Canyon State Park
Description - "Slow down or walk," says the sign at the entrance to the tiny hamlet of Eldorado Springs, and the sudden deterioration in road quality ensures that you have no other choices. But you wouldn't want to zoom past this town anyway. There's some decent riparian habitat along the river, and Red-eyed Vireos have been found in town doing things suspiciously similar to breeding. The views become increasingly spectacular as you get towards the entrance of the state park, which is framed by enormous cliffs. Near the entrance station, in the warmer months, you'll find Canyon Wrens caroling, dippers bouncing downstream, and squadrons of swifts and swallows dogfighting far above your head. Check the cottonwoods for migrants. Past the canyon mouth, the valley flattens out and mixed conifer forests press down against the road. The trail system here connects with the Walker Ranch and with the disjunct western section of Eldorado Canyon State Park several miles upstream, which contains more mixed conifer forest, ponderosa and mountain meadows.
URL - Eldorado Canyon State Park
Habitat - Lowland Riparian, Cliff Face, Stream, Mixed Conifer Forest, Ponderosa Forest, Mountain Meadows
Directions - From Boulder, take Broadway (CO 93) south out of town a few miles to its intersection with Eldorado Canyon Road (CO 170). Turn right (west) on Eldorado Canyon Road and follow it to and through the town of Eldorado Springs to the state park entrance. From Denver, take US 36 west and exit at Louisville/Superior (exit #...?) onto McCaslin Boulevard. Head south on McCaslin to CO 170 and turn right (west). Continue as above.
Delorme - 40 A1, 39 A7
Roads of Colorado - 56 B4
Waneka Lake
Aliases - Greenlee Natural Area
Description - (Submitted by Randy Siebert) The focus of this city park is a good-sized lake that serves as a city water supply. It has a 1.2 mile walking trail around the lake that is popular (visit early in the day). During the 2002 drought, the water was very low and shorebirds, including Sanderling, were numerous. The lake rarely if ever freezes over completely so winter geese and ducks can be good. Greater White-fronted and Snow Geese and a few good gulls make at least a brief appearance most years. Bald Eagles can be regular in January and February. Cottonwoods, willows, and cattails border the lake on the north and west. Swamp Sparrow and Winter Wren have been found in fall. Bullock's Orioles and Yellow Warbler are breeders. There is fairly good potential for migrants, which have included Rose-breasted Grosbeak and Blackpoll Warbler.

The Greenlee Natural Area adjoins the city park on the northwest corner. It features a small pond with marsh that can be seen from a viewing platform. Water levels are extremely variable. Ducks and shorebirds can be good. Some summers have a resident Black-crowned Night-heron.
URL - Waneka Lake
Habitat - Pond/Lake/Reservoir, Lowland Riparian, Marsh
Directions - To reach the east entrance of Waneka Park, from the intersection of US 287 (CO 7) and Baseline Road in Lafayette, drive west on Baseline about a half mile, then left (south) on Caria Drive. Walk north on the fitness trail to get to the Greenlee Natural Area. To reach the west entrance of the park, from the intersection of US 287 and South Boulder Road, head west a little over a mile to Centaur Village Drive and turn north. Turn left on Caria and follow it around to the west entrance of the park.
Delorme - 40 A2
Roads of Colorado - 56 C3
Valmont Reservoir complex
Aliases - Legion Park, Hillcrest Reservoir, Leggett-Owen Reservoir
Description - Valmont is merely the largest of the three reservoirs in this complex, the others being Hillcrest and Leggett-Owen. The Valmont complex is Boulder County's premier winter waterbird spot, since the Excel power plant usually keeps some water in these lakes open all winter. They can harbor large numbers of winter ducks of many species, and they often have small numbers of other birds that normally winter farther south, including grebes, pelicans, cormorants, Great Blue Herons and Killdeer. Most of Boulder County's winter gulls roost on Valmont, although not too many stick around during the day. Scoping from the open space at dusk is a good way to pick out rare gulls. When there is a very cold snap, Valmont may be the only open water in the area, and the concentrations of birds here can be astounding. Waterbird numbers may vary widely from one day to the next.

The area around the lakes is good for raptors in winter; Bald Eagle is common, Golden Eagle is uncommon, and Ferruginous Hawk is quite regular. Great Horned Owls have nested in the box that Excel has mounted high on the side of its smokestack, and Barn Owl has nested in an old Wood Duck box visible (at a tremendous distance) from Legion Park.

The reservoirs can be birded from two locations. From dawn to dusk they can be scoped from Legion Park to the south. This provides a good view of Hillcrest Reservoir and the only possible view of Leggett-Owen Reservoir, which is quite distant. Valmont Reservoir itself can only be partially scanned from Legion Park, and always at a great distance. Scoping all the trees and power poles from this vantage point gives you a decent shot at turning up both eagles in winter.

During weekday business hours (and occasionally and irregularly at other times) you can drive into the Open Space headquarters, park and walk west along the south shore of Valmont Reservoir. This is the best way to bird Valmont itself, and this is where you want to be to catch the incoming gulls on a winter evening. If the gate is not open you can park in front of it on the west side of 75th Street (being careful not to block the gate) and walk about three quarters of a mile out to the scanning spot.
Habitat - Pond/Lake/Reservoir, Grassland/Prairie, Hedgerow/Shelterbelt
Directions - Legion Park (open dawn to dusk) is on the north side of Arapahoe Road (CO 7) on the east side of Boulder, about 2.5 miles east of Foothills Parkway (CO 157) and 0.5 miles west of 75th Street. The entrance to the Open Space headquarters is on the west side of 75th Street about 0.6 miles north of Arapahoe.
Delorme - 30 D1
Roads of Colorado - 56 B3-C3
Humane Society Dog Walk Park
Aliases - Ball Brothers Grove
Description - A rich and open to the public area along Boulder Creek just west of 55th St. Decent birding at any season, but spring and fall migrations bring the promise of special treats. The area is a dense riparian section along Boulder Creek with a loop trail around a marshy area going to the south.
Resident birds present include House Wren, Yellow Warbler, Song Sparrow, American Robin, American Goldfinch, Red-winged Blackbird and Brown-headed Cowbird. Migrants and transients can include Lark Sparrow, Turkey Vulture, American Dipper Orange-crowned Warblers, Yellow-rumped Warblers, Western Tanagers and Bullock's Orioles.
Habitat - Stream, Lowland Riparian, Marsh
Directions - Park at the Humane Society of Boulder County on the west side of 55th Street between Arapahoe and East Pearl and head west toward the creek. For the best habitat follow the creek upstream and keep to the right, then follow the trail to the left. If you head back even further through the woods you will come to a City of Boulder "Open" Space fence that marks the beginning of the closed area, but you can follow along the fence line for good views into some dense riparian habitat. While there you are likely to encounter Humane Society volunteers exercising dogs.
Delorme - D1
Roads of Colorado -
Sombrero Marsh
Description - You never know what you are going to find at Sombrero Marsh. You might find a dusty clearing where Sombrero Pond used to be, or you might find a Garganey--both have occurred here. When water levels are right, this can be impressive shorebirding, and the marshes can be bustling with rails.
URL - Sombrero Marsh
Habitat - Pond/Lake/Reservoir
Directions - From Denver, take US 36 to Boulder, exiting onto Foothills Parkway north (note: this is a tricky double exit; take the right off of US 36 and then an immediate left to stay on Foothills). Follow Foothills Parkway (CO 157) north to Arapahoe, then turn right (east). Head east to the intersection with 63rd Street (stoplight) and turn right onto the Sombrero Marsh entrance road.
Delorme - 30 D1
Roads of Colorado - 56 B3
Teller Lake #5 and Culver Ponds
Aliases - Culver Ponds
Description - The small feedlot beside the Teller Lake Trailhead has sometimes attracted huge winter flocks of blackbirds, including Rusty. The surrounding area is one of the more regular spots in the county to find Great-tailed Grackle. The trees around the lake can be good for migrant warblers, and the lake itself can have waterfowl, though it usually hosts mostly Canada Geese.

The nearby Culver Ponds are somewhat tricky to scan well from the road, but they can be productive for ducks and gulls, and are particularly popular with Hooded Mergansers for some reason. Keep an eye out here for Great-tailed Grackles also. Beware swan sightings, though--an escaped, non-countable Trumpeter Swan has frequented the ponds in recent years.
URL - Teller Lake #5 and Culver Ponds
Habitat - Pond/Lake/Reservoir, Lowland Riparian, Hedgerow/Shelterbelt, Marsh
Directions - From Boulder, head east on Valmont Avenue. The Teller Lakes trailhead is on the south side of Valmont about two miles east of 75th Street. To get to Culver ponds, continue east another half mile on Valmont to the T intersection at 95th, then turn left (north). The ponds are on either side of 95th about half a mile north of Valmont.
Delorme - 30 D2
Roads of Colorado - 56 C3
Boulder Creek & 75th Street
Description - Adjacent to the Walden Ponds complex and connected to it by footpath, this birding spot has its own parking lot and is often birded separately. The creek here used to be kept open year-round thanks to the effluent from the Boulder water treatment plant. Now the outlet has been moved downstream from 75th street, and the birding is not as good west of the bridge. Access is restricted east of the bridge due to raptor nesting. The trees along the creek here can be excellent for spring migrants, including vagrant warblers.

To reach Walden Ponds on foot from the parking lot, just continue west along the creekpath and then follow it south along the east side of the water treatment plant. The woods along the creek to the west of the bend in the path, unfortunately, are private.
Habitat - Stream, Lowland Riparian, Grassland/Prairie
Directions - The parking lot is on the west side of 75th Street just south of its intersection with Jay Road, about 0.5 mile north of the turnoff to Walden Ponds and a little less than a mile north of Valmont Drive, east of Boulder.
Delorme - 30 D1
Roads of Colorado - 56 C3
Walden Ponds/Sawhill Ponds Complex
Aliases - Sawhill Ponds, Cottonwood Marsh
Description - This is one of Boulder's premier birding sites due to its wide variety of habitats. The Walden Ponds area is a Boulder County Open Space. The Sawhill Ponds area abuts it to the south, and the two are for all practical purposes the same, although they have different parking lots.
The largest and often the birdiest pond in the complex is Cottonwood Marsh, just north of the Walden Ponds parking lot. When water levels are low it can be excellent for shorebirds; when they are higher, for dabbling and diving ducks. Gulls, waders, cormorants, and other waterbirds are a good bet. During migration, swallows occasionally gather in enormous flocks over the water.
The marshy part of Cottonwood Marsh is traversed by a boardwalk just west of the Walden Ponds parking lot. Virginia Rail, Sora, and Wilson's Snipe breed here, and it can be a good spot for wintering sparrows possibly including a White-throated, Harris's or Swamp.
The numerous paths around the Walden/Sawhill complex provide access to a large number of ponds, each with its own water level and vegetative structure. Most of the regular waterbirds can be found here in season, though shorebird habitat outside Cottonwood Marsh is often limited. American Bittern is probably a regular summer resident, moving between the larger reedbeds, but it can be difficult to see or hear. Dawn and dusk may be your best bet, as with the Black-crowned Night-Herons that are more numerous and easier to see. The brush and trees around the ponds will produce all the typical birds of lowland woodland edge habitats, including some locally uncommon species like Eastern Kingbird and occasionally Orchard Oriole. Foothill birds like Rock Wren and Green-tailed Towhee can be common in migration.
The western edge of the main footpath loop gets close to the mature forests along the creek, skirting the best habitat for migrant and breeding landbirds. Great Horned Owl and Eastern Screech-Owl are resident in these woods. The creek, which runs to the west of the path, is your best bet for Wood Duck.
URL - Walden Ponds/Sawhill Ponds Complex
Habitat - Pond/Lake/Reservoir, Lowland Riparian, Marsh, Hedgerow/Shelterbelt, Stream
Directions - The Sawhill Ponds parking lot is at the end of a short, signed access road which heads west from 75th Street just north of the railroad crossing, about a half mile north of Valmont Drive east of Boulder. The Walden Ponds parking lot is at the end of its own short, signed access road which heads west from 75th Street a short distance north of the Sawhill Ponds access road.
Delorme - 30 D1
Roads of Colorado - 56 B3-C3
Highland Reservoir #2
Description - This rocky-shored, medium-sized lake might be worth a check during waterbird migration. It can be scanned from the south, from a couple of pullouts on the north side of Yellowstone Road (CR 2).
Habitat - Pond/Lake/Reservoir
Directions - From Longmont, head north out of town on US 287 three miles to Yellowstone Road (CR 2). Turn left (west). The reservoir is about two miles west on the north side of the road.
Delorme - 30 B1-C2
Roads of Colorado - 56 B2
Terry Lake and Clark Reservoir
Description - (Submitted by Bill Kaempfer) This large lake can host large congregations of birds, but they are frustratingly difficult to observe. Terry Lake is more than one mile long, and over one-half mile wide, but it is surrounded by private land and only approachable for a brief stretch on its west side. The lake is fairly deep and does not experience much variation in its water level. Consequently it is best for diving birds and not particularly good for shorebirds. Huge congregations of up to a thousand grebes and mergansers are not uncommon in late spring or early fall. Loons and terns are also likely. Nearby Clark Reservoir is a small lake, one of the better shorebird spots in the county when water levels are low; otherwise it's usually slow.
Habitat - Pond/Lake/Reservoir
Directions - Take CO 66 1.5 miles west of US 287 in Longmont to 95th St and turn right (north). Proceed along 95th St. for about 2 miles to the west bay of Terry for best viewing opportunities. Turn left and park along Woodland Rd. (be sure to obey any no parking signs) and walk back to scope the lake. For terns, look to several buoys in the south part of the lake. Clark Reservoir is southwest of Terry, on the south side of Vermillion Rd between 87th and 95th Street, two miles west of US 287 and one mile north of US 66.
Delorme - 30 C1-C2
Roads of Colorado - 56 C1-C2
McIntosh Lake
Description - (Submitted by Bill Kaempfer) Urban reservoirs can sometimes be devoid of waterfowl, but this locale is generally good, especially for waders, terns and, at times, shorebirds. McIntosh is a fairly large lake that the City of Longmont now operates as a public park, which has limited power boating and water skiing, while improving access. Oddly, there are some drawbacks to both of these points; markers in the water intended for boaters provided good perches for terns, and a proposed trail system around the lake may end up proving a disturbance to many species if it is too close to the shore, especially in the Northwest corner.
Habitat - Pond/Lake/Reservoir
Directions - In Longmont, take 17th Avenue west from US 287 for 2.5 miles and turn right (north) on Lakeshore Drive. Follow along Lakeshore Drive to view the lake from the south. Continue along Lakeshore, noting the cattail marsh at the east end of the lake which is good for Yellow-headed Blackbirds and possibly rails. Turn left on Harvard Street and then take the next left on North Shore Drive. In less than 0.5 miles a parking area on the left gives access to the north shore of the lake which can be good for fall shorebirds when the water level falls to expose some shore.
Delorme - 30 C1
Roads of Colorado - 56 C2
Pella Crossing Park
Aliases - Marlatt Open Space
Description - A few nice fishing ponds provide habitat for ducks and the occasional gull; a few noteworthy migrants have stopped in the bushes. Adjacent hayfields to the south and east (which are private and NOT open to the public, but can be birded from the park) have hosted breeding Dickcissel, Bobolink and Grasshopper Sparrow in some years.

At the north end of the Park, near the railroad tracks, is a path that connects Pella Crossing with Marlatt Open Space to the west on the other side of 75th Street, which has several more ponds and some trees worth checking.
Habitat - Pond/Lake/Reservoir
Directions - From Longmont, take CO 66 west to 75th Street and turn left (south); proceed one mile through the town of Hygiene. The entrance to Pella Crossing Park is on the east side of 75th Street just south of the railroad tracks, on the south end of Hygiene.
Delorme - 30 C1
Roads of Colorado - 56 C2
Reservoirs west of Hygiene
Aliases - Burch Lake, McCall Lake, Foothills Reservoir, McCaslin Lake
Description - The medium-sized Burch Lake and the smaller McCall Lake, both on the south side of CO 66, usually provide mundane birding, but interesting waterfowl have been known to show up. Burch must be scanned from the side of the highway through trees, while McCall is nearly encircled by access roads. Beware exotics in both places. Foothills Reservoir, to the southwest, is large but difficult to scan; your best bet is a pullout in front of a gate at the west end of the bend in Hygiene Road. The nearby McCaslin Lake is the smallest but often the birdiest of this group of reservoirs; look especially for diving ducks and goose flocks in winter.
Habitat - Pond/Lake/Reservoir
Directions - From Longmont, head west on CO 66. Burch Lake and McCall Lake are both on the south side of the highway, Burch about 3 miles west of US 287, just west of 75th Street, and McCall about a mile farther west. To get to the other lakes, turn left (south) on 63rd Street, which flanks the west end of McCall. At the T intersection with Hygiene Road, turn right (west). Ahead you will see the dam of Foothills Reservoir, which you can scan by continuing west along Hygiene Road. To get to McCaslin, turn left (south) before the dam onto CR 41, which curves around the west side of McCaslin about a half mile south of Hygiene Road.
Delorme - 30 C1
Roads of Colorado - 56 B2-C2
Rabbit Mountain Open Space
Description - A scrubby, isolated foothill, Rabbit Mountain is known as the most reliable spot in the county for Bushtit and Pinyon Jay, which is not to say it is particularly reliable for either species, but both can be seen there year-round. More regular are flocks of bluebirds. Keep an eye on the sky for raptors, frequently including Golden Eagle.
URL - Rabbit Mountain Open Space
Habitat - Mixed Conifer Forest
Directions - Head west on CO 66 from Longmont about five miles to 53rd Street. Turn right (north) on 53rd, which terminates a couple miles north in the parking lot for Rabbit Mountain.
Delorme - 30 C1
Roads of Colorado - 56 B1
Hall Ranch Open Space
Description - South of Lyons, this open space is popular with hikers and mountain bikers. The trail starts out in dry foothill scrub good for Western Scrub-Jay, Rock and Canyon Wrens, and winter flocks of juncos; with luck you may turn up a Bushtit or ten. During their late-summer post-breeding dispersal, Sage Thrashers show up around the parking lot, often in numbers, but they are rarely seen here at other times of year. After more than a mile the trail finally ascends into the lower ponderosa belt, although junipers and other dryland shrubs remain prevalent. The intrepid might be rewarded with a Western Bluebird or a Pinyon Jay.
URL - Hall Ranch Open Space
Habitat - Foothill Shrub, Ponderosa Forest
Directions - From Longmont or Boulder, head west on CO 66 or US 36, respectively, to the town of Lyons. Proceed through downtown Lyons and turn left at the T intersection to stay on CO 7 west. The parking lot for Hall Ranch is a few miles outside Lyons, on the right (north) side of the road.
Delorme - 30 C1
Roads of Colorado - 56 B2
Lyons Area
Aliases - Meadow Park, Bohn Park, South Saint Vrain Trail, Apple Valley Road, South Saint Vrain Road
Description - The small town of Lyons, famous as a speed trap, is also well-known as a place to find a great mix of spicy foothills birds and juicy migrants. Several places in town are worth checking, as are two nice roads just outside town.

The Lyons cemetery is small, but contains some mature cottonwoods that might be worth checking for migrants. Meadow Park, along CO 7 just south of its junction with US 36, has a little riparian habitat and some very impressive sandstone cliffs that are home to White-throated Swift and Canyon Wren; keep an eye out for the local Golden Eagle pair. Bohn Park provides access to the South Saint Vrain Trail, which runs along the river of the same name about half a mile in either direction from the park, through riparian woods worth birding at all seasons.

Apple Valley Road and South Saint Vrain Road are very similar roads—so similar, in fact, that they are sometimes confused. Both are paved rural residential roads that parallel the busy highway on the other side of the river, and both are flanked by riparian cottonwoods on one side and dryer foothill habitats on the other side. The difference between these roads is that they parallel different highways and rivers. Apple Valley Road loops off US 36 and follows the North Saint Vrain, while South Saint Vrain Road (a.k.a. 845 Rd) loops off CO 7 and follows its namesake. Both roads can produce good flocks of migrants in season, including vagrants from the east, and both can produce difficult Boulder County birds like Northern Pygmy-Owl (mostly in winter), Lewis's Woodpecker (summer), Bushtit and Pinyon Jay. Both roads are very narrow and winding, both run entirely through private property, and neither has pullouts anywhere besides its end. For these reasons, both roads are best birded on foot, by people willing to pay as much attention to the traffic as to the trees. To bird Apple Valley Road, park just west of the suspension bridge at the road's north entrance to US 36. To bird South Saint Vrain Road, park at Bohn Park in Lyons and follow the South Saint Vrain Trail a half mile upstream to the start of the road, birding all the way.
Habitat - Lowland Riparian, Foothill Scrub, Cliff Face, Stream, Urban/Suburban
Directions - Lyons lies just west of the junction of US 36 and CO 66, north of Boulder and west of Longmont. To get to the cemetery, turn north off of US 36 onto 3rd Street and follow it through a small jog to its end. To get to Bohn Park, turn south off US 36 onto 2nd Avenue and follow it across the river; the park is on the right (west). Meadow Park is on the west side of CO 7 one block south of its junction with US 36.
Delorme - 30 C1
Roads of Colorado - 56 B1-B2
Button Rock Preserve
Aliases - Longmont Reservoir
Description - The road in to this City of Longmont preserve is a beautiful one that passes through a lot of lower montane habitats. It is a good place to find dipper at all seasons and may have Northern Pygmy-Owl in the winter months. Beyond the parking lot, the preserve is walk-in only. Up the trail you will find two mountain reservoirs (the small Longmont Reservoir and, two miles farther up, the large Button Rock Reservoir, also known as Ralph Price Reservoir) as well as a lot of open ponderosa pine forest.
Habitat - Ponderosa Forest, Mixed Conifer Forest, Foothill Shrub, Stream, Cliff Face, Mountain Meadow, Streamside Willow
Directions - Follow US 36 west from Lyons to about three miles to Longmont Dam Rd (CR 80) and turn left (south). Follow CR 80 to its end at the preserve parking lot.
Delorme - 29 C7
Roads of Colorado - 56 A1-B2
Allenspark
Aliases - Fawn Brook Inn, Saint Vrain Mountain Trailhead
Description - This little mountain hamlet has become known as one of the more regular sites in the state for winter flocks of rosy-finches. The Fawn Brook Inn at the south end of town along the CO 7 business loop typically stocks an impressive array of seed feeders that are easily viewed from the road. Flocks of rosies may come in at any time, but are more regular in some winters than others, and are typically most reliable during inclement weather. Other regular feeder visitors include Steller's Jay, Black-capped and Mountain Chickadees, all three species of nuthatch, and all manner of juncos. You may also see Pine and Evening Grosbeaks, Song Sparrow, Pine Siskin, American Goldfinch, and Cassin's Finch. Even Northern Pygmy-Owl and Common Redpoll have been seen here, but they are certainly not to be expected. Birders are welcome to view the feeders, but donations of seed are greatly appreciated.

Take a walk around the rest of town when you are done with the Fawn Brook. Many of the above feeder birds have been seen elsewhere in town, especially at a set of feeders on the north side of Ski Road a few blocks west of the CO 7 business loop. The town and the feeders are worth checking in summer, too, being one of the more regular spots in the county for Band-tailed Pigeon (uncommon to rare), and a fantastic spot to find hummingbirds in late summer, with four species regular. If you are here in summer, you may want to follow Ski Road west of town to its end at the Saint Vrain Mountain Trailhead. This out-of-the-way spot is my favorite trailhead in Boulder County. It provides access to a beautiful trail which follows a small stream through aspen groves, lodgepole forest, flowery mountain meadows, and limber pine forest on its way to ptarmigan country. Butterfly diversity is high here, and the birds aren't bad either. Look for Cassin's Finch and Empidonax flycatchers, among other mountain birds.
Habitat - Mixed Conifer Forest, Aspen Grove, Urban/Suburban, Mountain Meadow, Lodgepole Forest
Directions - From Longmont or Boulder, head west on CO 66 or US 36, respectively, to the town of Lyons. Proceed through downtown Lyons and turn left at the T intersection to stay on CO 7 west, which will take you to Allenspark. Near Allenspark, follow signs for the CO 7 business loop, which will take you straight past the Fawn Brook Inn. From the business loop, you can follow Ski Road (FR 116) approximately 2.5 miles to the trailhead and small parking lot.
Delorme - 29 C6
Roads of Colorado - 55 F2
Ish Reservoir
Description - This is a good-sized, shallow reservoir owned by a hunting club and closed to the public, but easily scannable from the road. It can be great for waterbirds. If water levels are low, shorebirds can be numerous. Sometimes the lake dries up, creating winter longspur habitat.
Habitat - Pond/Lake/Reservoir
Directions - From Longmont, head three miles north on US 287 and turn right (east) on CR 2 (Yellowstone Road). Proceed one mile to 115th Avenue and turn left. Half a mile north, 115th skirts the eastern edge of the reservoir. Pull as far over as possible and scan from the road. Note that a small slice of the lake at its north end is in Larimer County.
Delorme - 30 B2
Roads of Colorado - 56 C1
Jim Hamm Nature Area
Description - This tiny park, with its tiny lake and its short row of trees, probably would not be anywhere near as popular if it were not right across the road from Union Reservoir (which is in Weld County). Due to its location, Jim Hamm often "skims off" birds from Union, and the friendly size of Jim Hamm ensures that if there are rarities here, you won't miss them. Waterbirds are usually the main attraction, but the trees and brush piles on the north side can have migrants and wintering landbirds as well.
Habitat - Pond/Lake/Reservoir, Hedgerow/Shelterbelt
Directions - From CO 119 just east of Longmont (4 miles west of I-25), turn north on County Line Road (sign for Union Reservoir). The nature area parking lot is on the left in just over two miles.
Delorme - 30 C2
Roads of Colorado - 56 C2
Gunbarrel and Niwot area
Aliases - Twin Lakes, Dodd Lake
Description - These two small unincorporated towns between Boulder and Longmont are not themselves great birding spots, but there are a few places in their vicinity worth mentioning. Perhaps the best-known among Boulder birders is the area around 79th and Lookout in Gunbarrel, one of the very few places in the county where you can still find Burrowing Owl. Scan all the fenceposts in the area and as much of the ground as you can see, all along 79th until it enters the subdivision. Dawn and dusk are best, and even then there is no guarantee of success.

The Twin Lakes in Gunbarrel have potential for waterfowl and (when water is low) shorebirds, and the surrounding trees can be very good for landbirds, particularly in migration. The trail that follows the creek south and west from the lakes along a riparian corridor through some housing developments also should be checked for migrants and wintering landbirds. There is a decent marsh on the west end of the property near the road.

Dodd Lake just west of Niwot can be a great place to find large flocks of winter geese, often including a Snow or a Greater White-fronted. Other ducks and gulls sometimes show up here when they're really bored. There is not much room to pull of the road here, but you can bird at ease from the northwest corner, which is open space. If the geese are not on the water, they may be feeding in any of the surrounding fields.

The field on the southeast corner of Jay Road and the Diagonal (CO 119) fills up with water during wet years, and can host shorebirds and ducks especially in the fall.
Habitat - Pond/Lake/Reservoir, Stream, Lowland Riparian, Grassland/Prairie
Directions - Gunbarrel and Niwot are both along CO 119 (the Diagonal Highway) between Boulder and Longmont. To get to the Burrowing Owl spot, take the Diagonal northeast from Boulder to the 63rd Street exit and take 63rd Street south a few blocks to Lookout. Turn left (west) on Lookout and follow it to 79th Street, which only heads left (north) from Lookout. To get to the Twin Lakes, follow directions as to the Burrowing Owl spot but keep going south on 63rd past Lookout to Nautilus Drive. Turn left (east) on Nautilus, then take another left at the stop sign. Park in the cul-de-sac at Eaton Park at the end of the street. To get to Dodd Lake, take the Diagonal to Niwot Road and turn left (west). Within a half mile, 73rd heads north from Niwot Road, which west of this intersection is no longer Niwot Road, but 71st Street. To get to the continuation of Niwot Road, you have to turn right (north) on 73rd and then take your first left onto Niwot. Dodd Lake is north of 71st, west of 73rd and south of Niwot Road, and can in theory be scanned from any of these roads, but you will have to be very careful about pulling off the road. Better yet, park in the open space lot northwest of the lake on Niwot Road and walk east into the publicly-accessible corner lot to scan the lake.
Delorme - 30 D1
Roads of Colorado - 56 B3
Cottonwood Trailhead and Hayden Lake
Aliases - Hayden Lake
Description - This county open space trail runs both north and south along a private wooded canal that has potential for landbirds at all times of year. The trailhead is adjacent to Hayden Lake, which looks like it could be good for waterfowl, but is shielded from view by a thick grove of trees. The lake can probably be adequately scanned (with some effort) when the leaves are off the trees, but not at other times of year.
URL - Cottonwood Trailhead and Hayden Lake
Habitat - Pond/Lake/Reservoir, Stream, Lowland Riparian, Grassland/Prairie
Directions - The trailhead is located on the south side of Independence Road in northeast Boulder. From northbound Foothills Parkway (CO 157), take the right exit labeled "Boulder" just as Foothills merges with CO 119/Diagonal Highway. Take your first left after the traffic becomes two-way, onto eastbound Independence Road. From central Boulder, take Iris Avenue/Diagonal Highway under the Foothills Parkway overpass, then turn right onto eastbound Independence Road. The trailhead is less than a half mile from the highway.
Delorme - 30 D1
Roads of Colorado - 56 B3
Boulder Reservoir
Aliases - Sixmile Reservoir, Coot Lake
Description - This City of Boulder park charges an entrance fee during the summer, but not during the winter. This is fortuitous for birders, as the colder months are definitely the better ones for birding here. Being the largest body of water in the county, Boulder Reservoir attracts rare waterbirds at a high rate. Loons, grebes and diving ducks are a good bet in migration, and jaegers and rare gulls and terns have shown up on occasion. Ospreys breed along the west shore, which is seasonally closed for that reason. From the east end of the entrance road, if you so desire, you can walk the dam north to get better views of distant birds. The main entrance road runs along the south shore of Boulder Reservoir and the north shore of the smaller Sixmile Reservoir, which can also be excellent for birds. For alternate access to Boulder Reservoir, you can park at one of the other parking lots, which will get you out of paying the entrance fee. One is in the northwest corner of the reservoir along 51st Street, and the other is in the northeast corner along 75th Street. Both require you to walk a quarter to a half mile in order to scan the water. The northeast parking lot is adjacent to Coot Lake, which can host marsh birds like rails, American Bittern, and roosting blackbirds, in addition to its namesake.
URL - Boulder Reservoir
Habitat - Pond/Lake/Reservoir
Directions - From Boulder, head northeast on the Diagonal Highway (CO 119) to Jay Road and turn left (west). Once on Jay, take an almost immediate right (north) just past the fire station onto 51st Street, which is signed for Boulder Reservoir. The main entrance is on the right in a little over a mile. To get to the northwest corner of the reservoir, continue on 51st Street another mile past the main entrance. To get to the northeast corner of the reservoir, instead of exiting the Diagonal at Jay Road, continue on it to 63rd Street and take a left (north). The parking lot for Coot Lake is on the left side of the road in about a mile.
Delorme - 30 D1
Roads of Colorado - 56 B3
Boulder Valley Ranch
Description - Most of this sprawling open space is open arid prairie with scattered yucca and prairie dog towns. It's not particularly good for most prairie birds, but the Ranch can be a great place to see raptors at any season (winter is best). In addition, there are a few ponds on the property that you have to hike some distance to get to, and a little bit of dry foothill scrub in a couple of places. The Sage Trail is probably the most interesting for birding; it follows a long line of mature cottonwoods and some underbrush along a canal for the better part of a mile. The trees are not themselves accessible, but they can be easily birded from the trail.
URL - Boulder Valley Ranch
Habitat - Short-grass Prairie, Yucca, Pond/Lake/Reservoir, Hedgerow/Shelterbelt
Directions - From the junction of US 36 and CO 7 at the north end of Boulder, travel north on the combined highway about a mile and turn right on Longhorn Road (signed for Boulder Valley Ranch). This dirt road, which can be badly washboarded, heads east about a mile to the main trailhead.
Delorme - 30 D1
Roads of Colorado - 56 B3
Left Hand Valley Reservoir area
Aliases - Spurgeon Reservoir #1, Fentress Lake, Loukonen Reservoir
Description - Left Hand Valley Reservoir is a large private reservoir surrounded by open space. It can be scanned at a distance from the parking lot, or at close range from the open space trail, although it is a bit of a hike to get to the areas close to the lakeshore.

Just to the north, Spurgeon Reservoir #1 (not labeled in DeLorme) is one of several area reservoirs operated by the Left Hand Water District. There is no access, but most of the reservoir can be scanned from a pullout at the northwest corner, right in front of the sign exhorting passersby to Report Suspicious Activity.

East of Left Hand Valley Reservoir is Fentress Lake, which doesn't look like much but seems to have a magnetic effect on swans. Three Trumpeters wintered here in 2002-2003, one the following winter, three Tundras spent some time here in fall 2004, and a Trumpeter wandered in and out for most of the following winter. Expect a few ducks and geese as well. If you suspect that swans are in the area, but they don't seem to be at Fentress, check Loukonen Reservoir and another golf course pond in the subdivision to the south.
Habitat - Lake/Pond/Reservoir, Grassland/Prairie
Directions - From the junction of US 36 and Jay Road, travel north a little less than three miles and turn right onto Neva Road. The parking lot for Left Hand Valley Reservoir is on the right (south) in one mile. Just east of the parking lot, turn left (north) on 39th and then left at the T intersection to scan Spurgeon Reservoir. To get to Fentress Lake, instead of turning on 39th, continue east on Neva Road. Fentress, not labeled on most maps, is in the Lake Valley Golf Club subdivision just north of Boulder. The lake is partly visible on the south side of Neva Road just east of Fairways Drive (a.k.a. 57 Rd, with a west-facing sign for the Lake Valley Golf Club). Best viewing is from the southwest corner of the lake at the intersection of Fairways Drive and Lake View Point. Please respect the lawns of landowners when pulling over. To get to Loukonen Reservoir, continue south on Fairways Drive to Niblick Drive and turn left; then turn right onto Ace Court, from which it is possible to view the reservoir. To scan the other golf course pond, continue on Niblick to its T intersection with Golf Club Drive and turn right; the pond is barely visible to the left, some distance from the road.
Delorme - 30 D1
Roads of Colorado - 56 B2-B3
Heil Valley Ranch
Aliases - Lefthand Canyon
Description - Nice and close to Boulder, this place can get busy with bikers and hikers. There are some beautiful ponderosa forests and mountain meadows along the trails; if you hike way back in, you can get to the rocky and arid foothills shrub zone.
Lefthand Canyon Road, which continues upslope all the way to the Peak-to-Peak highway at Ward, should be checked for foothill and mountain breeders including Veery along the stream in willowy patches.
URL - Heil Valley Ranch
Habitat - Ponderosa Forest, Mountain Meadow, Foothills Shrub, Cliff Face
Directions - From Boulder, head north out of town on US 36/CO 7 to Lefthand Canyon road. Turn left on Lefthand Canyon Road and then right in less than a mile onto Geer Canyon Road, which is signed for Heil Valley. The parking lot is 1.25 miles from Lefthand Canyon Road; the entrance road leads through a private working ranch, so please be respectful.
Delorme - 30 C1
Roads of Colorado - 56 B2
Panama Reservoir area
Description - Panama Reservoir is a large body of water that can be scanned with a little difficulty from the south, from the shoulder of busy CO 52.

East of Panama, just before it hits County Line Road, CO 52 passes a few gravel pit ponds that can be productive for waterfowl. The two on the north side of the road are surrounded by Russian-olives that obscure large parts of the water from easy view. The one south of the road is treeless. This pond and the westernmost north pond are best scanned from a nice large pullout on the north side of the highway that corresponds nicely with a gap in the Russian-olives. To scan the easternmost north pond, you can park across the road from it along the path to a farmer's gate.

The seasonally wet field south of CO 52 and west of County Line Road is the best place in Boulder County to find flocks of ibis and egrets in migration. Glossy Ibis has been seen here, and Cattle Egret is regular.
Habitat - Pond/Lake/Reservoir, Hedgerow/Shelterbelt, Wet Meadow
Directions - From Boulder, head northeast on the Diagonal Highway (CO 119) to CO 52 and turn right (east). Panama Reservoir is on the left in approximately five miles. The gravel pit ponds and wet fields are just beyond, west of County Line Road.
Delorme - 30 D2
Roads of Colorado - 56 C3
Little Gaynor Lake
Description - A waterfowl observation blind sits on the north side of this small lake, which has been remarkably productive in recent years for waterbirds. Ducks, especially diving ducks, are usually numerous, and the lake has produced such goodies as Ross' Goose, Greater Scaup and Sabine's Gull.
Habitat - Pond/Lake/Reservoir
Directions - Little Gaynor is between Niwot and Longmont, on the south side of Oxford Road east of 95th Street and west of US 287. From Longmont, head south on US 287 about 2.5 miles from the junction with CO 119. From Boulder, head northwest on CO 119 (the Diagonal) to Niwot Road. Drive east through the town of Niwot 2.5 miles to 95th Street, then one mile north to Oxford Road.
Delorme - 30 D2
Roads of Colorado - 56 C2
Lagerman Reservoir and the Swede Lakes
Aliases - Clover Basin Reservoir, Swede Lakes
Description - Lagerman is always worth a check. It seems to hold a particular attraction for small gulls, but may have egrets, geese, shorebirds, ducks, or nothing at all. The prairie dog town west of the lake is one of three county sites for Burrowing Owl; this area is also one of the better spots in winter and migration for Ferruginous Hawk. Northern Harrier and Osprey breed in the area. The surrounding fields have attracted longspurs and Short-eared Owl in winter.

The marshes at the middle Swede Lake are small, but in recent years have had breeding Great-tailed Grackle, Marsh Wren and rails.

A mile north of Lagerman is Clover Basin Reservoir, a medium-sized lake worth scanning from the shoulder of the rather busy Nelson Road along its south shore.
Habitat - Pond/Lake/Reservoir, Grassland/Prairie, Marsh
Directions - From Boulder, head northeast on CO 119 (the Diagonal) to Niwot Road. Go a quarter mile west on Niwot and then approximately 2.5 miles north on 73rd (which becomes 75th) to Pike Road. The parking lot for Lagerman Reservoir is on the south side of Pike Road, 0.5 miles west of 75th Street. The Swede Lakes are just west of the turnoff to the parking lot. Follow the road west and south a little farther to scan for Burrowing Owl. To get to Clover Basin Reservoir, keep going north on 75th one mile to Nelson Road and turn left (west).
Delorme - 30 C1
Roads of Colorado - 56 B2-C2
Saint Vrain Greenway
Aliases - Golden Ponds Nature Area, Longmont Sewage Treatment Plant, Boulder County Fairgrounds
Description - This walking and bike trail starts in the west at Golden Ponds Nature Area, a park full of gravel ponds and Russian-olive groves. It can have good numbers of birds, mostly of the citified variety, but goodies have shown up and the place may be worth checking for migrant landbirds and wintering waterfowl. Just across Hover Road to the east are the Boulder County Fairgrounds, which have a couple of ponds of their own, as well as some breeding Osprey.

The central parts of the greenway are pretty urban, but the city has extended the trail east of Main Street almost to the Longmont Sewage Treatment Plant. This has opened up some very nice riverside birding areas that were formerly closed. Unfortunately, the quality of some of the habitats has been diminished by the clearing of brush and the introduction of prairie-dogs. Furthermore, the best area of the creek, just south of the Sewage Treatment Plant, is out-of-bounds. However, the open parkland retains some small ponds and some decent riparian habitat for migrants and breeders. Currently the best place to park is in the parking lot of the strip mall on the west side of Main Street and the south side of the river.
Habitat - Pond/Lake/Reservoir, Lowland Riparian, Stream, Urban/Suburban
Directions - From Boulder, take the Diagonal (CO 119) to Longmont. To get to Golden Ponds and the fairgrounds, turn left (north) onto Hover Road. The fairgrounds are on the right just before (south of) the river. The entrance to Golden Ponds is on the left, just beyond (north of ) the river. To get to the eastern section of the greenway, do not turn onto Hover Road, but stay on CO 199 through the southern part of town all the way to Main Street. Turn left (north) on Main Street and park in the stripmall parking lot on the left (west) side of Main just south of the river.
Delorme - 30 C2
Roads of Colorado - 56 C2
Wild Basin
Aliases - Copeland Lake, Ouzel Falls
Description - This broad valley is one of the jewels of Rocky Mountain National Park. For better or for worse, it is a very long hike to the peaks from here, even from the end of the Wild Basin Road. But even without hiking, you've got decent shots here at both sapsuckers, all the willow specialties, and (especially in August) Black Swift.
Sandbeach Lake trailhead is just past the National Park entrance station. The first mile of the Sandbeach trail goes through the same excellent ponderosa forest you can see around Copeland Lake itself--just more of it. At about 1.2 miles the trail crests the ridge and from there to Sandbeach Lake the habitats are mostly lodgepole, mixed-conifer and spruce-fir. The birding up here can be good, if you're up to the hike.
Around Copeland Lake itself, look for all the ponderosa specialty birds, including Williamson's Sapsucker and Band-tailed Pigeon (rare). If you are here between June and early September, look high above the lake for flocks of Violet-green Swallows. You may see a Black Swift in with them, somewhere up in the stratosphere. If they are not over Copeland Lake, keep an eye out for them all the way up to the end of the road, and from there up the trail to Ouzel Falls and beyond.
Across the road from Copeland Lake are some interesting willow and aspen habitats which are fairly accessible, but often wet. Outside this immediate area, birding the road between here and its end can be problematic. The road is very windy and narrow in some places two cars may not be able to pass abreast. Park only in designated spots, and be very careful where you bird. At any rate, apart from a nice mountain meadow or two, there usually isn't much reason to stop between Copeland Lake and the Wild Basin trailhead.
The area around the Wild Basin trailhead can be fairly birdy, with an avifauna typical of the transition into a higher-elevation (but not spruce-fir) forest. The hike to Ouzel Falls is highly recommended. Especially if you are there early in the summer and early in the day, you have an excellent chance for a wide variety of montane birds on this medium-length hike. Beyond Calypso Cascades the trail passes through an old burn area, now rather too old for Three-toed Woodpeckers, but still attractive to Northern Pygmy-Owls, which nest in the snags, and which you may see if you are insanely lucky. Ouzel Falls itself has in recent years been the breeding site of the Black Swifts which now appear to be more regular in Wild Basin than anywhere else on the East Slope. Staking out the falls, however, is not a particularly good way to see the birds unless done at dawn or dusk, as they visit the nest very rarely during the day. Look for them overhead, or even below you if you are on one of the high points overlooking the valley. The wide variety of scenery and the relative ease of this hike make it a good choice for those traveling with non-birders.
Habitat - Ponderosa Forest, Aspen Grove, Stream, Streamside Willow, Mountain Meadow, Lodgepole Forest, Burn Area
Directions - The Wild Basin area is in the southeast portion of Rocky Mountain National Park. It is accessed via a signed road which heads west from CO 7 about two mile north of Allenspark and two miles south of Meeker Park.
Delorme - 29 C6
Roads of Colorado - 55 F2