BirdAnalyst
BBS Route · Colorado · BCR 16

Aspen Bird Survey Route

A standard 50-stop Breeding Bird Survey route. 107 species recorded across 40 survey years, still active.

107Species RecordedSpecies recordedDistinct species detected on standard-protocol BBS runs here across all years on record — a measure of survey breadth, not a complete checklist.Full methodology →
40Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →
1979–2025Span
7Observers

Bird Species Found on Colorado Aspen

Top 40 of 107 species by most recent count. Each links to its species trend.

Species recorded on the Aspen route.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →History
Violet-green SwallowHirundinidae94202519×1983
American RobinTurdidae532025-15%1983
Yellow WarblerParulidae412025+7%1983
Broad-tailed HummingbirdTrochilidae312025+21%1983
Warbling VireoVireonidae312025+169%1983
Song SparrowPasserellidae282025+37%1983
Black-billed MagpieCorvidae272025-51%1983
Chipping SparrowPasserellidae242025+370%1986
Western Wood-PeweeTyrannidae172025+192%1983
Northern House WrenTroglodytidae152025+163%1983
MacGillivray's WarblerParulidae132025+32%1984
Western TanagerCardinalidae122025+260%1985
Swainson's ThrushTurdidae122025+93%1983
Black-capped ChickadeeParidae112025+125%1984
American CrowCorvidae112025+175%1996
House FinchFringillidae102025+525%1989
Spotted TowheePasserellidae92025+767%1997
Common RavenCorvidae72025+300%1984
Bullock's OrioleIcteridae72025+300%1997
Brewer's BlackbirdIcteridae62024-87%1983
Green-tailed TowheePasserellidae62025-40%1984
Hermit ThrushTurdidae62006-25%1984
Mountain ChickadeeParidae62025+57%1986
Common NighthawkCaprimulgidae52010+400%2009
White-throated SwiftApodidae41990-67%1979
Pine SiskinFringillidae42025-77%1984
Ruby-crowned KingletRegulidae42025+60%1983
Virginia's WarblerParulidae42025-23%1990
House SparrowPasseridae42025+22%1985
Red-tailed HawkAccipitridae32025-11%1984
Brown-headed CowbirdIcteridae32025-42%1983
Red-winged BlackbirdIcteridae32025-65%1983
Lewis's WoodpeckerPicidae32023+20%2017
Dusky FlycatcherTyrannidae32021+50%1995
Orange-crowned WarblerParulidae32025+280%1994
Turkey VultureCathartidae32025+67%1997
Northern CardinalCardinalidae31990n/an/a
Cedar WaxwingBombycillidae32025+33%2002
American KestrelFalconidae22025-50%1984
Steller's JayCorvidae22025-25%1983

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14. A route is a sample, not a census.