BirdAnalyst
Guild · Illinois · BBS 2025 Release · 1966–2024

Generalists In Illinois

All statesIllinois

54 species in this guild. As a group they are -55%Guild trendA mean-index aggregate across the species in this group — the structural direction of the guild, with individual-species noise smoothed out.Full methodology → since 1968.

Guild SignalsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

guild collapsecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Generalists as a group have fallen sharply in Illinois, down 54% since 1968.

Generalists In Illinois Population Forecast

If the recent trend holds, Generalists in Illinois is projected to fall about 26% by 2029 — from 11 in 2024 to a central estimate of 7.9 (95% range 5.0–11). A 5-year backtest shows a typical error of ±12%, with 100% of held-out values landing inside the 95% band.

-26%Change by 2029TrendPercent 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 →
7.9Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
5.0–1195% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±12%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Generalists in Illinois is projected to fall about 26% by 2029 — from 11 in 2024 to a central estimate of 7.9 (95% range 5.0–11). A 5-year backtest shows a typical error of ±12%, with 100% of held-out values landing inside the 95% band.19662029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20258.85.912
20268.65.711
20278.35.511
20288.15.211
20297.95.011

Member Species In Illinois

Generalists species in Illinois.
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 →
Loggerhead ShrikeLaniidae-97%
Gray PartridgePhasianidae-96%
Black-billed CuckooCuculidae-91%
House SparrowPasseridae-82%
Common GrackleIcteridae-75%
Sharp-shinned HawkAccipitridae-75%
Rock PigeonColumbidae-71%
Northern HarrierAccipitridae-70%
Brown ThrasherMimidae-67%
Field SparrowPasserellidae-57%
Blue JayCorvidae-54%
Northern MockingbirdMimidae-51%
European StarlingSturnidae-43%
Swamp SparrowPasserellidae-39%
Yellow-billed CuckooCuculidae-29%
Broad-winged HawkAccipitridae-29%
Eastern Screech-OwlStrigidae-28%
Great Horned OwlStrigidae-27%
Red-winged BlackbirdIcteridae-25%
American KestrelFalconidae-19%
Belted KingfisherAlcedinidae-18%
Song SparrowPasserellidae-17%
Baltimore OrioleIcteridae-5%
American GoldfinchFringillidae-1%
American CrowCorvidae+15%
Mourning DoveColumbidae+19%
Eastern TowheePasserellidae+34%
Gray CatbirdMimidae+57%
Northern CardinalCardinalidae+75%
Orchard OrioleIcteridae+86%
Indigo BuntingCardinalidae+88%
Rose-breasted GrosbeakCardinalidae+97%
Scarlet TanagerCardinalidae+98%
Black VultureCathartidae+112%
Brown-headed CowbirdIcteridae+155%
Red-tailed HawkAccipitridae+178%
Yellow-breasted ChatIcteriidae+179%
Eurasian Tree SparrowPasseridae+294%
OspreyPandionidae+316%
Mississippi KiteAccipitridae+348%
Barred OwlStrigidae+379%
Cedar WaxwingBombycillidae+633%
Fish CrowCorvidae+824%
Cooper's HawkAccipitridae+982%
Chipping SparrowPasserellidae13×
Ruby-throated HummingbirdTrochilidae14×
Bald EagleAccipitridae18×
Red-shouldered HawkAccipitridae21×
Wild TurkeyPhasianidae25×
House FinchFringillidae26×
Summer TanagerCardinalidae29×
Eurasian Collared-DoveColumbidae37×
Blue GrosbeakCardinalidae46×
Turkey VultureCathartidae52×

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.