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

Fish Crow Population Trend in Illinois

All statesGeneralists

Fish Crow in Illinois has surged: up 824% on the route-weighted index since 1972.

+824%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 →
25Routes 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 →
49YearsYears 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 824% 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 stay roughly flat through 2029, near 0.44 (95% range 0.24–0.64). A 5-year backtest shows a typical error of ±44.6%, with 60% of held-out values landing inside the 95% band.

+10%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 →
0.44Projected 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 →
0.24–0.6495% 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 →
±44.6%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 stay roughly flat through 2029, near 0.44 (95% range 0.24–0.64). A 5-year backtest shows a typical error of ±44.6%, with 60% of held-out values landing inside the 95% band.19702029
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 →
20250.410.200.61
20260.410.210.62
20270.420.220.63
20280.430.230.64
20290.440.240.64

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 →
Dudleyville820232021
Belknap620241999
Mascoutah Lk520242005
Pulaski420241971
Sandusky420231993
Payson320172008
Belleview320232021
Mt Vernon320242022
Delwood320232010
Kell320242024
St Morgan220222003
Beaucoup220242019
Bremen220241997
Karnak220242007
Darmstadt220242005
Cave In Rock220231995
Gulfport120232023
Pawnee120232023
Columbia120222004
Jamestown120192018
Olney120142014
Flora120142014
Beaverdam Lk120231970
Royalton120232003
Brownville120242024

Fish Crow Population Trend in Other States

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

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