BirdAnalyst
BBS Route · Colorado · BCR 16

Castleton Bird Survey Route

A standard 50-stop Breeding Bird Survey route. 112 species recorded across 31 survey years, still active.

112Species 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 →
31Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →
1988–2024Span
4Observers

Bird Species Found on Colorado Castleton

Top 40 of 112 species by most recent count. Each links to its species trend.

Species recorded on the Castleton 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
Red-winged BlackbirdIcteridae1182024-62%1992
American RobinTurdidae622024-58%1992
Yellow WarblerParulidae452024-24%1992
Black-billed MagpieCorvidae43202419×1996
Western Wood-PeweeTyrannidae312024+165%1992
White-crowned SparrowPasserellidae292024-14%1992
Savannah SparrowPasserellidae272024-24%1994
Warbling VireoVireonidae272024+493%1994
Pine SiskinFringillidae242024+63%1992
Green-tailed TowheePasserellidae242024+156%1994
Brewer's BlackbirdIcteridae232024-43%1994
Lincoln's SparrowPasserellidae232024+82%1994
Broad-tailed HummingbirdTrochilidae222024+30%1992
Tree SwallowHirundinidae182024-55%1994
Western TanagerCardinalidae152024+633%1994
House SparrowPasseridae152024-60%1994
Ruby-crowned KingletRegulidae142024+28%1996
Wilson's SnipeScolopacidae122024-12%1992
Song SparrowPasserellidae122024+61%1996
Western MeadowlarkIcteridae102024-26%1992
Cliff SwallowHirundinidae102024-85%1994
White-throated SwiftApodidae101991n/an/a
Northern House WrenTroglodytidae72024-30%1994
Eurasian Collared-DoveColumbidae72024+11%2010
European StarlingSturnidae62024-77%1992
House FinchFringillidae62024+0%1998
MacGillivray's WarblerParulidae62024+200%1996
Red CrossbillFringillidae62022-47%2003
Cassin's FinchFringillidae52024-63%1994
Hermit ThrushTurdidae52024-7%1996
Western BluebirdTurdidae51992+25%1991
Fox SparrowPasserellidae52024+433%2010
Cinnamon TealAnatidae52021n/an/a
Mourning DoveColumbidae42024-73%1992
Violet-green SwallowHirundinidae42024-82%1992
Horned LarkAlaudidae41991n/an/a
Black-capped ChickadeeParidae42024-10%1996
Dusky FlycatcherTyrannidae42024-15%1998
Bullock's OrioleIcteridae42023+200%2001
KilldeerCharadriidae32023-86%1992

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