Ring-necked ducks nest in mountain lakes, beaver ponds, and marshes near coniferous and aspen forests (Andrews and Righter 1992). Boulder County breeding populations appear to be stable (Hallock 1998). Dave Hallock observed a pair of ring-necked ducks at Giggey Lake, on Reynolds Ranch Open Space, during summer 1996.

Sharp-shinned Hawk

Colorado Natural Heritage Watchlist; Audubon Society Blue List

In Boulder County, sharp-shinned hawks typically nest in dense conifers in foothills canyons (Platt 1973, Weinberg 1987). Nesting populations appear to be declining in parts of the central and eastern United States (Ehrlich et al. 1992). Dave Hallock observed a sharp-shinned hawk in mixed coniferous forest in Boulder Canyon during summer 1996.

Cooper’s Hawk

Colorado Natural Heritage Watchlist; Audubon Blue List.

Cooper’s hawks typically nest in Boulder County foothills and mountain forests, often in dense conifers (Weinberg 1987). Nesting populations may be declining in parts of North America (Ehrlich et al. 1992). Dave Hallock observed Cooper’s hawks in mixed coniferous forest at two locations in Boulder Canyon during summer 1996.

Northern Goshawk

Federal Candidate; Colorado Natural Heritage Rare in State; U.S. Forest Service Vulnerable; Boulder County Declining.

Northern goshawks nest in mature aspen, ponderosa pine, and lodgepole pine forests throughout the mountains of Colorado (Andrews and Righter 1992). In Boulder County, where they have nested from approximately 1,900-3,000 m, they often select secluded north-facing canyons containing large ponderosa pines (Ellis and Parrish 1986, Jones 1987). Because of their apparent affinity for undisturbed forests, northern goshawks may be adversely affected by forest fragmentation. Dave Hallock observed nesting goshawks in mixed coniferous forest in Boulder Canyon near Castle Rock during summer 1996. Volunteers documented a northern goshawk nesting territory in mixed coniferous forest west of Forsythe Rock during July 1997.

Golden Eagle

Colorado Natural Heritage Watchlist; Boulder County Isolated Populations

Golden eagles nest in the foothills and mountains of Boulder County. Most nest sites are on cliff faces. Nesting populations (about 8-12 nesting pairs) appear to have remained stable since the late nineteenth century (Jollie 1945, Lederer and Armstead 1996). A nesting territory in Boulder Canyon, within the Magnolia study area, was first described by Ernest Greenman during the 1920s (Cushman, Jones, and Knopf 1993). This territory has been continuously active since 1982 (Lederer and Armstead 1996). The most frequently used nest site within this territory lies on Eagle Rock, on the south side of the canyon 2 km below Boulder Falls. The Eagle Rock nest fledged a total of 8 young during 8 nestings from 1984-97 (Nancy Lederer, pers. comm.). Volunteers frequently saw eagles near Twin Sisters during spring 1997, but no nesting activity was observed at this location.

Peregrine Falcon

Federal Endangered; State Threatened; U.S. Forest Service Vulnerable; Boulder County Rare and Stable.

Peregrine falcons typically nest on cliff faces at low to mid-elevations in the mountains of Colorado (Andrews and Righter 1992). In 1964, there were only 6 documented active nests in Colorado and none in Boulder County. Since then, nesting populations have increased steadily to more than 60 active nests in the state and 3-4 active nests in Boulder County (Jerry Craig, Colo. Div. of Wildl., pers. comm., Lederer and Armstead 1996). Active nests in the Flatirons rock formation west and southwest of Boulder lie within 10 km of the eastern study area boundary. Volunteers observed soaring peregrine falcons near Forsythe Rock during the 1996 and 1997 breeding seasons.

Flammulated Owl

U.S. Forest Service Vulnerable; Boulder County Isolated Populations.

Flammulated owls nest in Boulder County aspen groves and ponderosa pine/Douglas-fir forest from approximately 2000-2800 m (Jones 1991). Highest Colorado nesting densities occur in mature ponderosa pine forests in roadless foothills canyons (Reynolds and Linkhart 1987, Jones 1991). These insectivorous owls may be vulnerable to disturbance and fragmentation of mature ponderosa pine forests. Volunteers heard a calling flammulated owl at 2550 m on Winiger Ridge on May 31 1996.

Three-toed Woodpecker

Colorado Natural Heritage Watchlist; U.S. Forest Service Vulnerable; Boulder County Isolated Populations.

Three-toed woodpeckers nest in Colorado spruce-fir, Douglas-fir, lodgepole pine, and ponderosa pine forests (Andrews and Righter 1992). Since they frequently forage in burn areas, populations may be adversely affected by suppression of natural fires. Population trends in Boulder County have not been documented sufficiently to indicate an upward or downward trend (Hallock 1998). Volunteers observed foraging three-toed woodpeckers in Douglas-fir forest in four north-facing canyons on the Reynolds Ranch and Platt-Rogers properties, and in ponderosa pine/Douglas-fir forest west of Forsythe Rock and near Miramonte. Dave Hallock found an active nest in Boulder Canyon near Castle Rock.

Olive-sided Flycatcher

U.S. Forest Service Vulnerable

Olive-sided flycatchers nest in mature spruce-fir forests (Andrews and Righter 1992). They have been included in a U.S. Forest Service list of vulnerable species. Indian Peaks Bird Count data do not indicate an upward or downward population trend in Boulder County (Hallock 1998). Volunteers observed this species in ponderosa pine/Douglas-fir forests throughout the study area.

Willow Flycatcher

U.S. Forest Service Vulnerable; Boulder County Declining and Isolated Populations.

Willow flycatchers nest in Colorado foothills and montane riparian thickets (Andrews and Righter 1992). Nesting populations have declined throughout much of the western United States, and the southwestern subspecies has been listed as Endangered by the U.S. Fish and Wildlife Service (Ehrlich et al. 1992). Boulder County nesting populations appear to have declined dramatically since the early twentieth century (Henderson 1908, Boulder County Audubon Society 1978-97, Hallock 1998). Volunteers observed a singing willow flycatcher in a willow carr near Pinecliffe on June 27 and July 12, 1997.

Pygmy Nuthatch

U.S. Forest Service Vulnerable; Boulder County Isolated Populations

Pygmy nuthatches nest almost exclusively in ponderosa pine forests (Andrews and Righter 1992). Cutting of firewood and expansion of subdivisions into Colorado ponderosa pine forests have resulted in loss of nest sites and in local population declines (Webb 1985). Volunteers observed pygmy nuthatches throughout the study area.

Golden-crowned Kinglet

U.S. Forest Service Vulnerable; Boulder County Isolated Populations

Golden-crowned kinglets nest primarily in mature spruce-fir forest (Andrews and Righter 1992). Their affinity for old-growth makes them vulnerable to forest disturbance and fragmentation. Dave Hallock observed singing golden-crowned kinglets in mixed Douglas-fir/ponderosa pine/Engelmann spruce forest on Reynolds Ranch south of Boulder Creek during summer 1996.

Veery

Colorado Natural Heritage Watchlist; Boulder County Rare and Stable

Small numbers of veeries nest in Boulder County montane willow carrs. Dave Hallock observed a singing veery in riparian woodland on Reynolds Ranch during summer 1996.

Savannah Sparrow

Colorado Natural Heritage Watchlist; Boulder County Isolated Populations

Savannah sparrows nest in wet meadows, irrigated hay fields, and marsh edges throughout much of Colorado (Andrews and Righter 1992). In Boulder County, mountain populations appear to have declined since the early 1900s, possibly because of elimination of hay cultivation in mountain meadows (Henderson 1908, Hallock 1998). Volunteers observed singing savannah sparrows in wet meadows near Giggey Lake and near the intersection of Magnolia and Twin Sisters roads, and also nesting in the wet meadow of Scates Ranch. Dave Hallock confirmed savannah sparrows nesting near Giggey Lake.

Fox Sparrow

U.S. Forest Service Vulnerable; Boulder County Isolated Populations

Fox sparrows nest primarily in Colorado montane willow carrs (Andrews and Righter 1992). They are uncommon summer residents of montane willow carrs in several mountain locations in Boulder County. Volunteers observed singing fox sparrows in a willow carr below Barker Reservoir and in riparian woodland west of Forsythe Rock.

Evening Grosbeak

Colorado Natural Heritage State Imperiled

Evening grosbeaks nest in mid-elevation coniferous forests throughout the mountains of Colorado (Andrews and Righter 1992). Because of the secretive nature of breeding populations (they nest colonially and do not advertise breeding territories by singing), little is known about Boulder County nesting populations (Hallock 1998). Volunteers observed evening grosbeaks in mixed coniferous forest south of Barker Reservoir, west of Forsythe Rock, and south of Comforter Mountain.

Table 5.3 Potential Breeding Species: Birds seen or heard in suitable nesting habitat, Magnolia Area: 1 June-15 August, 1995-97

Habitat Codes: A-aspen, C-coniferous forest, G-grassland, L-lake/pond, R-riparian woodland/shrubland, S-shrubland, T-rock and talus, U-urban/structure, W-wetland
Boldface: Boulder County species of special concern (Hallock 1993)
Underline: Confirmed nesting

Table 5.4 Avian Species of Special Concern

¹Federal Codes:
LE: Endangered
C2: Formerly notice of review, category 2. This category was dropped from the Federal Register on February 28, 1996.

²Colorado Natural Heritage Program Codes:
G4: Apparently secure globally, though it may be quite rare in parts of its range, especially at the periphery.
G5: Demonstrably secure globally, though it may be quite rare in parts of its range, especially at the periphery.
S2: Imperiled in state because of rarity (6 to 20 occurrences), or because of other factors demonstrably making it very vulnerable to extirpation from the state.
S3: Rare in state (21 to 100 occurrences).
S3S4: Watchlisted; specific occurrence data are collected and periodically analyzed to determine whether more active tracking is needed.
B: Breeding season imperilment, summer-resident species.
T: Colorado Division of Wildlife, state threatened.

³USFS REGION 2: Vulnerable species:
2: Declining but not yet rare.
3: Rare and stable.
5: Isolated or restricted populations.

⁴Boulder County Nature Association Codes:
2: Declining but not yet rare.
3: Rare and stable.
5: Isolated or restricted populations.

Literature Cited

Andrews, R., and R. Righter. 1992. Colorado Birds. Denver Museum of Natural History, Denver.

Boulder County Audubon Society. 1978-97. Monthly wildlife inventories. P.O. Box 2081, Boulder CO 80306.

Colorado Natural Heritage Program. 1996. Colorado’s heritage: rare and imperiled animals, plants, and natural communities. Vol. 2, No.1. College of Natural Resources, 103 Natural Resources, Fort Collins, CO 80523-1401.

Cushman, R., S. Jones, and J. Knopf. 1993. Boulder County Nature Almanac. Pruett Publishing Co., Boulder.

Ehrlich, P., D. Dobkin, and D. Wheye. 1992. Birds in Jeopardy: the Imperiled and Extinct Birds of the United States and Canada. Stanford University Press, Stanford CA.

Ellis, K. and J. Parrish. 1986. Hawks of the forest. Colorado Outdoors, Jan./Feb., 24-27.

Hallock, D. 1993. Boulder County avian species of special concern. Boulder County Parks and Open Space, 13^th and Spruce, Boulder CO 80302.

Hallock, D. 1998. Indian Peaks Bird Counts fifteen year summary. Boulder County Nature Association. P.O. Box 493, Boulder CO 80306.

Henderson, J. 1908. An annotated list of the birds of Boulder County, Colorado. University of Colorado Studies 6:220-242.

Jollie, M.T. 1945. Notes on raptors of the Boulder area, Colorado. Condor 47: 38-39.

Jones 1987 Hawks, Eagles and Prairie Dogs: Wintering raptors in Boulder County, Colorado. Boulder County Nature Association, Publication #8, Dec. 1987

Jones, S. 1991. Distribution of small forest owls in Boulder County, Colorado. Colorado Field Ornithologists Journal, summer 1991.

Lederer, N. and S. Armstead. 1996. Cliff-nesting raptors in Boulder County and vicinity, 1994 and 1995 status report. Boulder County Nature Association, P.O. Box 493, Boulder CO 80306.

Reynolds, R. and B. Linkhart. 1987. The nesting biology of flammulated owls in Colorado. Symposium on Biology and conservation of Northern Forest Owls. USDA Forest Service General Technical Report RM-142.

Platt, J. 1973. Sharp-shinned hawk nesting and nest site selection in Utah. Condor 78:102-103.

Tate, J. 1986. The blue list for 1986. American Birds 40 (2): 227-237.

Webb, B. 1985. Birds subgroup report. B. Winternitz and D. Crumpacker eds., Colorado wildlife workshop--species of special concern. Colorado Division of Wildlife, Denver.

Weinberg, H. 1987. The accipiter census. Unpublished manuscript.