BirdAnalyst
BBS Route · Colorado · BCR 16

Guanella Pas Bird Survey Route

A standard 50-stop Breeding Bird Survey route. 81 species recorded across 31 survey years, still active.

81Species 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 →
1992–2024Span
3Observers

Bird Species Found on Colorado Guanella Pas

Top 40 of 81 species by most recent count. Each links to its species trend.

Species recorded on the Guanella Pas 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 RobinTurdidae402024+85%1994
Warbling VireoVireonidae272024+54%1994
Ruby-crowned KingletRegulidae222024+4%1994
Canada GooseAnatidae192008n/an/a
Hermit ThrushTurdidae152024-36%1994
Broad-tailed HummingbirdTrochilidae132024-48%1994
Mountain ChickadeeParidae102024-44%1994
Lincoln's SparrowPasserellidae92024+96%1994
Clark's NutcrackerCorvidae82024+233%1995
American CrowCorvidae72024+500%2001
White-crowned SparrowPasserellidae62024-42%1994
Pine SiskinFringillidae52024-48%1994
MacGillivray's WarblerParulidae52024+60%1999
Red CrossbillFringillidae52024-55%2003
Wilson's WarblerParulidae42024-15%1994
Northern House WrenTroglodytidae42024-41%1994
Cliff SwallowHirundinidae42018+480%2001
American DipperCinclidae42024+25%2017
Steller's JayCorvidae32024+22%1994
Brown-headed CowbirdIcteridae32023-14%1994
Chipping SparrowPasserellidae32024-25%1999
Violet-green SwallowHirundinidae32024-77%1994
Golden-crowned KingletRegulidae32019-46%1994
Townsend's SolitaireTurdidae32024+43%1995
White-throated SwiftApodidae32009+200%1997
Hammond's FlycatcherTyrannidae32018+133%2005
Brewer's SparrowPasserellidae32006+200%2001
Canada JayCorvidae32019+75%2008
Red-tailed HawkAccipitridae22023+0%1994
Red-naped SapsuckerPicidae22024-33%1994
Olive-sided FlycatcherTyrannidae22024+0%1997
Western Wood-PeweeTyrannidae22023+75%1996
Green-tailed TowheePasserellidae22024+67%1995
Orange-crowned WarblerParulidae22011-50%1992
Swainson's ThrushTurdidae22024-20%1995
Tree SwallowHirundinidae22021+14%1995
Red-breasted NuthatchSittidae22024+0%1999
Red-winged BlackbirdIcteridae22017+40%1997
Cassin's FinchFringillidae22012-56%2001
MallardAnatidae22019-33%1996

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