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

Dickcissel Population Trend in Illinois

All statesGrassland birds

Dickcissel in Illinois has declined: down 37% on the route-weighted index since 1968.

-37%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 Dickcissel 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 →

No notable trend signals for Dickcissel in Illinois. See the full index history below.

Dickcissel Population Forecast in Illinois

If the recent trend holds, Dickcissel in Illinois is projected to fall about 25% by 2029 — from 29 in 2024 to a central estimate of 22 (95% range 1.4–42). A 5-year backtest shows a typical error of ±47.5%, with 80% of held-out values landing inside the 95% band.

-25%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 →
22Projected 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 →
1.4–4295% 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 →
±47.5%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, Dickcissel in Illinois is projected to fall about 25% by 2029 — from 29 in 2024 to a central estimate of 22 (95% range 1.4–42). A 5-year backtest shows a typical error of ±47.5%, with 80% 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 →
2025221.742
2026221.642
2027221.642
2028221.542
2029221.442

Dickcissel Survey Routes in Illinois

Routes recording Dickcissel 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 →
Beaucoup11920241971
Greenview7420241993
Buda6820231977
Stillwell6820241971
Concord West6720232001
Melrose6219991973
Brnt Prairie5820241976
Harristown5820242006
Duncan Mills5620241993
Chandlervill5520241971
Fairland5520241967
York5120241993
Humboldt5020241970
Kell5020242001
Bluff Spgs4920241967
Rosamond4920241972
Guilford4820231967
Dailey4720221967
Streator4520241972
Camp Point4520241993
Payson4420242000
Royalton4320242001
Fairbury4220241976
Jamestown4220241966
Eldred4220211993

Dickcissel Population Trend in Other States

alabamaarkansascoloradodelawaregeorgiaindianaiowakansaskentuckylouisianamarylandmichiganminnesotamississippimissourimontananebraskanew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniasouth-carolinasouth-dakotatennesseetexasvirginiawest-virginiawisconsinwyoming

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