BirdAnalyst
BBS Route · Colorado · BCR 18

Hudson Bird Survey Route

A standard 50-stop Breeding Bird Survey route. 94 species recorded across 35 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 →
35Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →
1988–2025Span
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
European StarlingSturnidae3202025+14%1990
House SparrowPasseridae3192025+7%1990
Western MeadowlarkIcteridae1842025-15%1990
Common GrackleIcteridae1242025+46%1990
Cliff SwallowHirundinidae122202514×1993
Red-winged BlackbirdIcteridae962025-60%1990
Western KingbirdTyrannidae762025+9%1990
Mourning DoveColumbidae562025+10%1990
Horned LarkAlaudidae562025+38%1990
American RobinTurdidae392025+14%1990
Eurasian Collared-DoveColumbidae132025+220%2007
Double-crested CormorantPhalacrocoracidae122025+52%1990
Barn SwallowHirundinidae112025-57%1990
Lark SparrowPasserellidae102025-39%1990
American CrowCorvidae102003+900%1993
Cassin's SparrowPasserellidae92025-60%1990
Canada GooseAnatidae92025+23%1996
KilldeerCharadriidae82025-54%1990
Ferruginous HawkAccipitridae81999+300%1993
White-faced IbisThreskiornithidae82012+60%2006
American White PelicanPelecanidae72025+29%1997
Swainson's HawkAccipitridae72025+100%1990
Bullock's OrioleIcteridae72025-64%1990
Upland SandpiperScolopacidae41999-30%1993
Ring-necked PheasantPhasianidae42025-74%1990
GadwallAnatidae32021+33%1995
Brown-headed CowbirdIcteridae32025-25%1991
Yellow-headed BlackbirdIcteridae32025-72%1990
Ring-billed GullLaridae32004-14%1996
Common NighthawkCaprimulgidae32022+25%1991
American GoldfinchFringillidae32023-17%1996
BobolinkIcteridae32022-50%2009
Black-necked StiltRecurvirostridae32018+200%2015
MallardAnatidae22025-87%1990
American KestrelFalconidae22025-42%1990
Burrowing OwlStrigidae22024-33%1991
Black-billed MagpieCorvidae22025-69%1990
House FinchFringillidae22025-13%1990
Song SparrowPasserellidae22023+33%1999
Lark BuntingPasserellidae22025-94%1990

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