BirdAnalyst
Species · Illinois · BBS 2026 Release · 1966–2025

Fish Crow Population Trend in Illinois

All statesGeneralists

Fish Crow in Illinois has surged: up 12× on the route-weighted index since 1972.

12×Since 1972TrendPercent 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 →
26Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
50YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Fish Crow Trends in IllinoisNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc increasecomputed 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 →

Fish Crow has surged in Illinois: up 12× on the route-weighted index since 1972.

Fish Crow Population Forecast in Illinois

If the recent trend holds, Fish Crow in Illinois is projected to fall about 49% by 2030 — from 0.99 in 2025 to a central estimate of 0.50 (95% range 0.24–0.76). A 5-year backtest shows a typical error of ±33.4%, with 60% of held-out values landing inside the 95% band.

-49%Change by 2030TrendPercent 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 →
0.50Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.24–0.7695% 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 →
±33.4%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, Fish Crow in Illinois is projected to fall about 49% by 2030 — from 0.99 in 2025 to a central estimate of 0.50 (95% range 0.24–0.76). A 5-year backtest shows a typical error of ±33.4%, with 60% of held-out values landing inside the 95% band.19702030
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 →
20260.460.200.72
20270.470.210.73
20280.480.220.73
20290.490.230.74
20300.500.240.76

Fish Crow Survey Routes in Illinois

Routes recording Fish Crow in Illinois.
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 →
Mascoutah Lk1720252005
Belknap1220251999
Bremen720251997
Beaucoup620252019
Mt Vernon620252022
Royalton620252003
Pulaski420251971
Dudleyville420252021
Sandusky420231993
Payson320172008
Kell320252024
Karnak320252007
St Morgan220222003
Cave In Rock220231995
Gulfport120232023
Belleview120252021
Pawnee120232023
Columbia120222004
Jamestown120252018
Olney120142014
Flora120142014
Delwood120252010
Beaverdam Lk120231970
Eldred120252025
Darmstadt120252005

Fish Crow Population Trend in Other States

alabamaarkansasconnecticutdelawarefloridageorgiaindianaiowakansaskentuckylouisianamainemarylandmassachusettsmississippimissourinew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniarhode-islandsouth-carolinatennesseetexasvermontvirginiawest-virginia

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.