BirdAnalyst
BBS Route · Iowa · BCR 22

Pierson Bird Survey Route

A standard 50-stop Breeding Bird Survey route. 94 species recorded across 38 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 →
38Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →
1968–2025Span
7Observers

Bird Species Found on Iowa Pierson

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

Species recorded on the Pierson 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
Red-winged BlackbirdIcteridae1382025-32%1970
American RobinTurdidae812025+73%1970
House SparrowPasseridae782025-74%1970
Barn SwallowHirundinidae642025+120%1970
DickcisselCardinalidae592025-62%1970
Ring-necked PheasantPhasianidae502025-45%1970
Common YellowthroatParulidae282025-25%1970
European StarlingSturnidae262025-55%1970
KilldeerCharadriidae232025+238%1970
Western MeadowlarkIcteridae232025-92%1970
Brown-headed CowbirdIcteridae222025+42%1970
Common GrackleIcteridae222025+0%1970
Northern House WrenTroglodytidae222025-44%1970
Chipping SparrowPasserellidae212025+725%1970
Canada GooseAnatidae162019+118%1997
Mourning DoveColumbidae152025-55%1970
Cliff SwallowHirundinidae152019+133%1996
Horned LarkAlaudidae142025-7%1970
American GoldfinchFringillidae132025-35%1970
Rock PigeonColumbidae82025+85%1970
Eastern KingbirdTyrannidae82025-71%1970
Vesper SparrowPasserellidae82025-59%1970
Song SparrowPasserellidae82025-78%1971
Western KingbirdTyrannidae72009+600%1970
Eurasian Collared-DoveColumbidae72025+10%2017
Eastern Wood-PeweeTyrannidae62025+0%1976
Bank SwallowHirundinidae6201820×1976
Warbling VireoVireonidae62025+200%1978
Yellow-headed BlackbirdIcteridae62014+700%2007
Red-headed WoodpeckerPicidae52025-66%1970
Savannah SparrowPasserellidae52012+14%1996
Gray CatbirdMimidae42025+233%1973
American CootRallidae42009+300%1976
Baltimore OrioleIcteridae32025-70%1970
Blue GrosbeakCardinalidae32025+60%1975
Northern Rough-winged SwallowHirundinidae32019+125%1971
Loggerhead ShrikeLaniidae32003+150%1982
American KestrelFalconidae32013-14%1973
Orchard OrioleIcteridae32019+300%1990
Tree SwallowHirundinidae32019-89%1997

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