BirdAnalyst
BBS Route · Colorado · BCR 16

Weston Pass 2 Bird Survey Route

A standard 50-stop Breeding Bird Survey route. 67 species recorded across 23 survey years, still active.

67Species 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 →
23Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →
2001–2025Span
2Observers

Bird Species Found on Colorado Weston Pass 2

Top 40 of 67 species by most recent count. Each links to its species trend.

Species recorded on the Weston Pass 2 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
White-crowned SparrowPasserellidae252025-17%2004
American RobinTurdidae242025-11%2004
Warbling VireoVireonidae222025+38%2005
Broad-tailed HummingbirdTrochilidae202025-17%2004
Lincoln's SparrowPasserellidae162025-44%2004
Pine SiskinFringillidae132025-60%2004
Ruby-crowned KingletRegulidae132025-41%2004
Horned LarkAlaudidae122025-55%2004
Mountain ChickadeeParidae102025-33%2004
Common RavenCorvidae92025-42%2004
Vesper SparrowPasserellidae92025+35%2005
Hermit ThrushTurdidae92025-60%2004
Steller's JayCorvidae72025+113%2004
Violet-green SwallowHirundinidae62025+40%2004
American CrowCorvidae62025+50%2024
Tree SwallowHirundinidae52025-27%2004
Chipping SparrowPasserellidae52025-15%2007
Dusky FlycatcherTyrannidae42025-27%2004
Clark's NutcrackerCorvidae42025-10%2009
Western TanagerCardinalidae42025+133%2004
Canada JayCorvidae42022+40%2007
Brown-headed CowbirdIcteridae32023-59%2004
Brewer's BlackbirdIcteridae32024-53%2004
Green-tailed TowheePasserellidae32025+43%2004
Wilson's SnipeScolopacidae22022-53%2004
Mourning DoveColumbidae22025-13%2004
Hairy WoodpeckerPicidae22025-20%2004
Red-naped SapsuckerPicidae22024-41%2004
Black-billed MagpieCorvidae22025-21%2005
Fox SparrowPasserellidae22025+71%2005
Cliff SwallowHirundinidae22025-86%2004
Sage ThrasherMimidae22012+100%2006
Brewer's SparrowPasserellidae22024-33%2013
Townsend's SolitaireTurdidae22023-17%2015
KilldeerCharadriidae12014+0%2005
Western Wood-PeweeTyrannidae12025-67%2004
European StarlingSturnidae12007-80%2001
Red-winged BlackbirdIcteridae12022-56%2004
Western MeadowlarkIcteridae12025-47%2004
Cassin's FinchFringillidae12024+33%2007

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