BirdAnalyst
BBS Route · Colorado · BCR 16

Guanella Pas Bird Survey Route

A standard 50-stop Breeding Bird Survey route. 82 species recorded across 32 survey years, still active.

82Species 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 →
32Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →
1992–2025Span
3Observers

Bird Species Found on Colorado Guanella Pas

Top 40 of 82 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 RobinTurdidae502025+131%1994
Ruby-crowned KingletRegulidae282025+5%1994
Hermit ThrushTurdidae282025+0%1994
Warbling VireoVireonidae272025+78%1994
Pine SiskinFringillidae242025+10%1994
Canada GooseAnatidae192008n/an/a
Lincoln's SparrowPasserellidae182025+91%1994
Broad-tailed HummingbirdTrochilidae122025-51%1994
White-crowned SparrowPasserellidae112025-34%1994
Wilson's WarblerParulidae112025-21%1994
Steller's JayCorvidae92025+67%1994
Mountain ChickadeeParidae92025-39%1994
Clark's NutcrackerCorvidae82024+233%1995
Common RavenCorvidae62025+11%1994
Violet-green SwallowHirundinidae62025-77%1994
Chipping SparrowPasserellidae52025+25%1999
Red CrossbillFringillidae52025-45%2003
Pine GrosbeakFringillidae42025+22%1996
Dusky FlycatcherTyrannidae42025+167%2001
Cliff SwallowHirundinidae42018+480%2001
American CrowCorvidae42025+467%2001
American DipperCinclidae42024+25%2017
Green-tailed TowheePasserellidae32025+17%1995
Northern House WrenTroglodytidae32025-29%1994
Golden-crowned KingletRegulidae32019-46%1994
Mountain BluebirdTurdidae32025+67%1995
White-throated SwiftApodidae32009+200%1997
Western TanagerCardinalidae32025-17%2004
Hammond's FlycatcherTyrannidae32018+133%2005
Brewer's SparrowPasserellidae32006+200%2001
Red-tailed HawkAccipitridae22025+25%1994
Olive-sided FlycatcherTyrannidae22025+25%1997
Orange-crowned WarblerParulidae22011-50%1992
Townsend's SolitaireTurdidae22025+57%1995
Black-billed MagpieCorvidae22025+0%1996
Fox SparrowPasserellidae22025-65%1995
Red-breasted NuthatchSittidae22024+0%1999
Red-winged BlackbirdIcteridae22017+40%1997
MacGillivray's WarblerParulidae22025+60%1999
Cassin's FinchFringillidae22025-44%2001

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