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BBS Route · Illinois · BCR 22

Williamsfld Bird Survey Route

A standard 50-stop Breeding Bird Survey route. 99 species recorded across 50 survey years, still active.

99Species Recorded
50Years Surveyed
1971–2024Span
3Observers

Bird Species Found on Illinois Williamsfld

Top 40 of 99 species by most recent count. Each links to its species trend.

Species recorded on the Williamsfld route.
History
Red-winged BlackbirdIcteridae902024+12%1974
House SparrowPasseridae742024-74%1974
American RobinTurdidae732024+500%1974
Canada GooseAnatidae452024+892%1985
Common GrackleIcteridae322024-3%1974
DickcisselCardinalidae322024+26%1974
Cliff SwallowHirundinidae32202411×1995
Barn SwallowHirundinidae242024+27%1974
KilldeerCharadriidae23202420×1977
Indigo BuntingCardinalidae222024+191%1978
Turkey VultureCathartidae222024+800%2001
European StarlingSturnidae202024+189%1974
Chipping SparrowPasserellidae202024+800%1974
Horned LarkAlaudidae182024-59%1976
Brown-headed CowbirdIcteridae162024+8%1977
Northern House WrenTroglodytidae162024+500%1976
Eastern MeadowlarkIcteridae142024-29%1974
American CrowCorvidae122024+208%1974
Eurasian Tree SparrowPasseridae122024+311%2005
House FinchFringillidae122024+173%1994
Mourning DoveColumbidae112024+292%1974
Northern CardinalCardinalidae102024+314%1974
Common YellowthroatParulidae92024+143%1974
Chimney SwiftApodidae92024-71%1978
Eastern KingbirdTyrannidae82024+200%1974
Warbling VireoVireonidae82024+383%1978
American GoldfinchFringillidae62024+47%1974
Western MeadowlarkIcteridae62019-56%1977
Rock PigeonColumbidae62024-42%1978
Rose-breasted GrosbeakCardinalidae62024+183%1977
BobolinkIcteridae52014-18%1977
Red-headed WoodpeckerPicidae42023-30%1976
Purple MartinHirundinidae42024-68%1974
Song SparrowPasserellidae42024-45%1976
Gray CatbirdMimidae42024+75%1978
Red-bellied WoodpeckerPicidae42024+133%1980
MallardAnatidae32019-65%1977
Northern BobwhiteOdontophoridae32024-93%1974
Eastern PhoebeTyrannidae32024+100%1989
Tufted TitmouseParidae32023-33%1976

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