BirdAnalyst
BBS Route · Colorado · BCR 16

Walden Bird Survey Route

A standard 50-stop Breeding Bird Survey route. 88 species recorded across 30 survey years, still active.

88Species 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 →
30Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →
1990–2025Span
5Observers

Bird Species Found on Colorado Walden

Top 40 of 88 species by most recent count. Each links to its species trend.

Species recorded on the Walden 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
Brewer's SparrowPasserellidae592025+40%1992
Vesper SparrowPasserellidae412025+132%1992
Savannah SparrowPasserellidae382025+53%1992
American White PelicanPelecanidae352025+352%1993
Canada GooseAnatidae352025+223%1993
Wilson's SnipeScolopacidae342025-8%1992
Sage ThrasherMimidae292025+22%1992
Red-winged BlackbirdIcteridae262025+37%1992
Cliff SwallowHirundinidae262025+133%1992
Horned LarkAlaudidae232025-16%1992
Black-billed MagpieCorvidae17202517×2006
White-crowned SparrowPasserellidae132025+538%1998
Northern PintailAnatidae122001+133%1993
Common RavenCorvidae102025+222%1993
Western MeadowlarkIcteridae102025-15%1992
Yellow WarblerParulidae102025-30%1992
MallardAnatidae92025+67%1992
Green-tailed TowheePasserellidae82025+57%1992
Common MerganserAnatidae72023-42%2002
American CrowCorvidae72025-50%1992
American RobinTurdidae72025-26%1992
Brown-headed CowbirdIcteridae62025-14%1992
American WigeonAnatidae52015-41%1992
Mountain BluebirdTurdidae52025-58%1992
Green-winged TealAnatidae52017-43%1999
American CootRallidae52021+167%1996
Brewer's BlackbirdIcteridae42025-14%1992
California GullLaridae42025-31%1993
Tree SwallowHirundinidae42023-40%1996
Common NighthawkCaprimulgidae42025+150%1997
Great Blue HeronArdeidae42019+150%2001
Ring-billed GullLaridae32024-92%1990
CanvasbackAnatidae32019+0%2001
KilldeerCharadriidae32025-71%1992
Swainson's HawkAccipitridae32022-8%1992
Yellow-headed BlackbirdIcteridae32025+11%1992
American GoldfinchFringillidae32025+75%2004
Song SparrowPasserellidae32025+125%1999
Blue-winged TealAnatidae32003+50%2001
SoraRallidae32017n/an/a

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