BirdAnalyst
BBS Route · Colorado · BCR 18

Hudson Bird Survey Route

A standard 50-stop Breeding Bird Survey route. 94 species recorded across 34 survey years, still active.

94Species 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 →
34Years 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
3Observers

Bird Species Found on Colorado Hudson

Top 40 of 94 species by most recent count. Each links to its species trend.

Species recorded on the Hudson 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
House SparrowPasseridae3342024+10%1990
European StarlingSturnidae1912024-3%1990
Common GrackleIcteridae1542024+39%1990
Western MeadowlarkIcteridae1202024-17%1990
Red-winged BlackbirdIcteridae722024-54%1990
Horned LarkAlaudidae692024+67%1990
Western KingbirdTyrannidae542024+16%1990
Mourning DoveColumbidae372024+22%1990
American RobinTurdidae172024+11%1990
Barn SwallowHirundinidae152024-54%1990
KilldeerCharadriidae142024-48%1990
Canada GooseAnatidae142023+21%1996
Cliff SwallowHirundinidae132024+533%1993
Lark SparrowPasserellidae122024-23%1990
Cassin's SparrowPasserellidae122024-50%1990
Eurasian Collared-DoveColumbidae112024+327%2007
Swainson's HawkAccipitridae102024+78%1990
American CrowCorvidae102003+900%1993
California GullLaridae92024-57%1990
Rock PigeonColumbidae82024-82%1990
Ferruginous HawkAccipitridae81999+300%1993
White-faced IbisThreskiornithidae82012+60%2006
Double-crested CormorantPhalacrocoracidae72024+24%1990
Bullock's OrioleIcteridae62024-56%1990
Upland SandpiperScolopacidae41999-30%1993
Brown-headed CowbirdIcteridae42024+0%1991
Say's PhoebeTyrannidae42024+200%2000
MallardAnatidae32024-86%1990
GadwallAnatidae32021+33%1995
Ring-billed GullLaridae32004-14%1996
Great Blue HeronArdeidae32024-55%1992
Common NighthawkCaprimulgidae32022+25%1991
American GoldfinchFringillidae32023-17%1996
BobolinkIcteridae32022-50%2009
Black-necked StiltRecurvirostridae32018+200%2015
Ring-necked PheasantPhasianidae22023-65%1990
American KestrelFalconidae22024-8%1990
Burrowing OwlStrigidae22024-33%1991
Black-billed MagpieCorvidae22024-63%1990
Yellow-headed BlackbirdIcteridae22024-60%1990

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