BirdAnalyst
BBS Route · Colorado · BCR 16

Delta Bird Survey Route

A standard 50-stop Breeding Bird Survey route. 127 species recorded across 47 survey years, still active.

127Species 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 →
47Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →
1973–2021Span
4Observers

Bird Species Found on Colorado Delta

Top 40 of 127 species by most recent count. Each links to its species trend.

Species recorded on the Delta 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
Mourning DoveColumbidae202021-41%1975
Warbling VireoVireonidae192021+185%1975
American RobinTurdidae162021+29%1975
Common RavenCorvidae142021+78%1976
Pine SiskinFringillidae132021+39%1975
Rock WrenTroglodytidae132021-35%1975
BushtitAegithalidae122021+567%1983
Horned LarkAlaudidae112021+9%1975
Chipping SparrowPasserellidae112021-42%1975
Western TanagerCardinalidae102021+46%1975
Bewick's WrenTroglodytidae82021+240%1976
Spotted TowheePasserellidae82021+33%1977
Violet-green SwallowHirundinidae82021+122%1976
Turkey VultureCathartidae72012+233%1991
Ash-throated FlycatcherTyrannidae72021+122%1975
Black-billed MagpieCorvidae72021-32%1975
Green-tailed TowheePasserellidae72021-35%1975
Virginia's WarblerParulidae72021-33%1975
Ruby-crowned KingletRegulidae72021+317%1976
Gray FlycatcherTyrannidae72021+300%1978
Woodhouse's Scrub-JayCorvidae72021+183%1977
Brewer's BlackbirdIcteridae72021+89%1977
Blue-gray GnatcatcherPolioptilidae62021+0%1975
Mountain BluebirdTurdidae62019+22%1975
Hermit ThrushTurdidae62021+90%1976
Red CrossbillFringillidae62019-23%2012
Dusky FlycatcherTyrannidae52021+80%1975
Lark SparrowPasserellidae42021+71%1976
Orange-crowned WarblerParulidae42021+233%1982
American CrowCorvidae42021-40%1976
Cinnamon TealAnatidae41998n/an/a
Pinyon JayCorvidae32021-8%1975
House FinchFringillidae32021-30%1975
Northern House WrenTroglodytidae32021+75%1975
White-crowned SparrowPasserellidae32017+50%1978
Black-headed GrosbeakCardinalidae32021+30%1976
Steller's JayCorvidae32021+133%1981
Juniper TitmouseParidae32021+82%1981
Lesser GoldfinchFringillidae32015+0%1992
Western MeadowlarkIcteridae22021+20%1975

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