BirdAnalyst
BBS Route · Iowa · BCR 22

Pierson Bird Survey Route

A standard 50-stop Breeding Bird Survey route. 93 species recorded across 37 survey years, still active.

93Species 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 →
37Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →
1968–2019Span
6Observers

Bird Species Found on Iowa Pierson

Top 40 of 93 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 BlackbirdIcteridae552019-52%1970
American RobinTurdidae522019+52%1970
Common GrackleIcteridae492019+66%1970
Brown-headed CowbirdIcteridae472019+30%1970
Barn SwallowHirundinidae342019+93%1970
DickcisselCardinalidae272019-65%1970
Ring-necked PheasantPhasianidae162019-65%1970
Mourning DoveColumbidae162019-46%1970
Horned LarkAlaudidae162013-34%1970
Canada GooseAnatidae162019+118%1997
European StarlingSturnidae152019-60%1970
Cliff SwallowHirundinidae152019+133%1996
KilldeerCharadriidae112019+250%1970
Lark SparrowPasserellidae92014+500%1998
Rock PigeonColumbidae82018+55%1970
Chipping SparrowPasserellidae82019+400%1970
Warbling VireoVireonidae82014+133%1978
Western KingbirdTyrannidae72009+600%1970
Eastern KingbirdTyrannidae62019-78%1970
Great Crested FlycatcherTyrannidae61988+250%1973
Bank SwallowHirundinidae6201820×1976
Yellow-headed BlackbirdIcteridae62014+700%2007
Rose-breasted GrosbeakCardinalidae52018+157%1985
Field SparrowPasserellidae52019-35%2000
Savannah SparrowPasserellidae52012+14%1996
BobolinkIcteridae42014-74%1970
Common YellowthroatParulidae42019-60%1970
House SparrowPasseridae42019-94%1970
Gray CatbirdMimidae42019+433%1973
Brown ThrasherMimidae42019-49%1970
Northern House WrenTroglodytidae42019-83%1970
American CootRallidae42009+300%1976
Eastern MeadowlarkIcteridae42013+33%2009
Eurasian Collared-DoveColumbidae42019-10%2017
American GoldfinchFringillidae32019-23%1970
Blue GrosbeakCardinalidae32018+280%1975
Northern Rough-winged SwallowHirundinidae32019+125%1971
Loggerhead ShrikeLaniidae32003+150%1982
American KestrelFalconidae32013-14%1973
Orchard OrioleIcteridae32019+300%1990

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