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

Gray Catbird Population Trend in Illinois

All statesGeneralists

Gray Catbird in Illinois has risen sharply: up 57% on the route-weighted index since 1968.

+57%Since 1968TrendPercent 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 →
105Routes 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 →
58YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Gray Catbird 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 →

Gray Catbird has risen sharply in Illinois: up 56% on the route-weighted index since 1968.

Gray Catbird Population Forecast in Illinois

If the recent trend holds, Gray Catbird in Illinois is projected to stay roughly flat through 2029, near 5.0 (95% range 3.6–6.3). A 5-year backtest shows a typical error of ±28.7%, with 20% of held-out values landing inside the 95% band.

-5%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 →
5.0Projected 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 →
3.6–6.395% 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 →
±28.7%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, Gray Catbird in Illinois is projected to stay roughly flat through 2029, near 5.0 (95% range 3.6–6.3). A 5-year backtest shows a typical error of ±28.7%, with 20% 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 →
20254.83.56.2
20264.93.56.2
20274.93.56.3
20284.93.66.3
20295.03.66.3

Gray Catbird Survey Routes in Illinois

Routes recording Gray Catbird 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 →
Belleview3120241966
Sheffield2820241966
Terre Haute2020241966
Melrose1919991973
Mill Creek1420241966
Alden1420232019
Athensville1320241971
Lake Galena1320212001
Geneseo1220211967
Wayne1220241966
Monica1220191973
Seneca1220241993
Atkinson1120241966
Shannon1120241993
Lake Summerset1120222001
Guilford1020231967
Buda1020231979
Stillwell1020241971
Beaucoup1020241971
Caledonia1020241993
Sherrard1020241993
Duncan Mills1020241993
Bartonville920241973
Concord920241967
Keithsburg920222001

Gray Catbird Population Trend in Other States

alabamaarizonaarkansascoloradoconnecticutdelawarefloridageorgiaidahoindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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