BirdAnalyst
BBS Route · Illinois · BCR 23

Guilford Bird Survey Route

A standard 50-stop Breeding Bird Survey route. 101 species recorded across 50 survey years, still active.

101Species 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 →
50Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →
1967–2023Span
8Observers

Bird Species Found on Illinois Guilford

Top 40 of 101 species by most recent count. Each links to its species trend.

Species recorded on the Guilford 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 BlackbirdIcteridae2392023+0%1969
American RobinTurdidae522023+177%1969
Eastern MeadowlarkIcteridae492023-15%1973
DickcisselCardinalidae482023+291%1969
House SparrowPasseridae422023-53%1969
Brown-headed CowbirdIcteridae352023+450%1969
American CrowCorvidae332023+42%1969
Northern CardinalCardinalidae312023+270%1969
Cliff SwallowHirundinidae302023+860%1980
Chipping SparrowPasserellidae28202315×1974
Common YellowthroatParulidae272023+541%1969
Field SparrowPasserellidae252023-49%1969
American GoldfinchFringillidae202023+144%1969
Mourning DoveColumbidae192023+93%1969
Song SparrowPasserellidae192023+15%1969
BobolinkIcteridae172023+100%1974
Warbling VireoVireonidae16202313×1979
Barn SwallowHirundinidae142023+161%1969
Red-bellied WoodpeckerPicidae132023+867%1969
Rose-breasted GrosbeakCardinalidae132023+133%1973
Northern Rough-winged SwallowHirundinidae13202338×1978
Northern House WrenTroglodytidae122023+100%1973
American RedstartParulidae112023+367%2007
Blue JayCorvidae102023-37%1969
European StarlingSturnidae102023-14%1969
Gray CatbirdMimidae102023+292%1969
Red-headed WoodpeckerPicidae82023-41%1969
Black-capped ChickadeeParidae82021-21%1978
MallardAnatidae62021+125%1988
Cedar WaxwingBombycillidae62022-13%1982
Eastern Wood-PeweeTyrannidae62023+88%1979
Canada GooseAnatidae62023+12%2003
Eastern KingbirdTyrannidae52023+24%1973
Horned LarkAlaudidae52023-57%1969
Indigo BuntingCardinalidae52023+129%1973
White-breasted NuthatchSittidae52022+22%1977
Belted KingfisherAlcedinidae42023-14%1969
Baltimore OrioleIcteridae42023+89%1969
Eastern TowheePasserellidae42023-8%1974
Black-billed CuckooCuculidae42023-25%1978

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