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Species · Illinois · BBS 2026 Release · 1966–2025

Gray Catbird Population Trend in Illinois

All statesForest birds

Gray Catbird in Illinois has risen sharply: up 64% on the route-weighted index since 1968.

+64%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 →
59YearsYears 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 64% 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 fall about 21% by 2030 — from 6.5 in 2025 to a central estimate of 5.1 (95% range 3.7–6.5). A 5-year backtest shows a typical error of ±26%, with 20% of held-out values landing inside the 95% band.

-21%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 →
5.1Projected 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 →
3.7–6.595% 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 →
±26%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 fall about 21% by 2030 — from 6.5 in 2025 to a central estimate of 5.1 (95% range 3.7–6.5). A 5-year backtest shows a typical error of ±26%, with 20% of held-out values landing inside the 95% band.19662030
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 →
20265.03.66.4
20275.03.66.4
20285.03.66.5
20295.13.76.5
20305.13.76.5

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 →
Terre Haute3220251966
Sheffield2820241966
Belleview2720251966
Caledonia2320251993
Eubanks2220252001
Stillwell2020251971
Melrose1919991973
Wayne1520251966
Athensville1520251971
Concord1320251967
Camp Point1320251993
Lake Galena1320212001
Monica1220191973
Sherrard1220251993
Lake Summerset1220252001
Atkinson1120241966
Bradbury1120251970
Guilford1020231967
Buda1020231979
Bartonville1020251973
Shannon1020251993
Kell1020252001
Seneca920251993
Payson920252001
Keithsburg920252001

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 2026-08-14.