BirdAnalyst
BBS Route · Colorado · BCR 16

Weston Pass 2 Bird Survey Route

A standard 50-stop Breeding Bird Survey route. 67 species recorded across 22 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 →
22Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →
2001–2024Span
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
American RobinTurdidae282024-15%2004
White-crowned SparrowPasserellidae262024-33%2004
Warbling VireoVireonidae222024+73%2005
Horned LarkAlaudidae142024-45%2004
Ruby-crowned KingletRegulidae112024-28%2004
Broad-tailed HummingbirdTrochilidae92024-26%2004
Vesper SparrowPasserellidae82024+24%2005
Mountain ChickadeeParidae82024-24%2004
Lincoln's SparrowPasserellidae72024-63%2004
Mountain BluebirdTurdidae72024-49%2004
Western Wood-PeweeTyrannidae62024-50%2004
Pine SiskinFringillidae62024-68%2004
Fox SparrowPasserellidae62024+86%2005
Chipping SparrowPasserellidae62024-35%2007
Dusky FlycatcherTyrannidae52024-27%2004
Common RavenCorvidae52024-49%2004
Hermit ThrushTurdidae52024-57%2004
Western MeadowlarkIcteridae42024-29%2004
Green-tailed TowheePasserellidae42024+14%2004
Violet-green SwallowHirundinidae42024+20%2004
Wilson's WarblerParulidae42024-60%2004
Canada JayCorvidae42022+40%2007
American CrowCorvidae42024n/an/a
Black-billed MagpieCorvidae32022-14%2005
Steller's JayCorvidae32024+50%2004
Clark's NutcrackerCorvidae32024-40%2009
Brown-headed CowbirdIcteridae32023-59%2004
Brewer's BlackbirdIcteridae32024-53%2004
Tree SwallowHirundinidae32024-35%2004
Wilson's SnipeScolopacidae22022-53%2004
Red-naped SapsuckerPicidae22024-41%2004
Black-headed GrosbeakCardinalidae22021-43%2005
Western TanagerCardinalidae22024+33%2004
Cliff SwallowHirundinidae22024-82%2004
Red CrossbillFringillidae22023-31%2007
White-breasted NuthatchSittidae22023-33%2007
Sage ThrasherMimidae22012+100%2006
Brewer's SparrowPasserellidae22024-33%2013
Townsend's SolitaireTurdidae22023-17%2015
KilldeerCharadriidae12014+0%2005

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. A route is a sample, not a census.