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

Loggerhead Shrike Population Trend in Illinois

All statesGeneralists

Loggerhead Shrike in Illinois has collapsed: down 97% on the route-weighted index since 1968.

-97%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 →
66Routes 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 →
54YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Loggerhead Shrike 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 declinecomputed 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 →

Loggerhead Shrike has collapsed in Illinois: down 97% on the route-weighted index since 1968.

Loggerhead Shrike Population Forecast in Illinois

If the recent trend holds, Loggerhead Shrike in Illinois is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.30). A 5-year backtest shows a typical error of ±717%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.00Projected 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 →
0.00–0.3095% 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 →
±717%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, Loggerhead Shrike in Illinois is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.30). A 5-year backtest shows a typical error of ±717%, with 100% 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 →
20250.000.000.30
20260.000.000.30
20270.000.000.30
20280.000.000.30
20290.000.000.30

Loggerhead Shrike Survey Routes in Illinois

Routes recording Loggerhead Shrike 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 →
Melrose419861986
Chandlervill319731973
Athensville319821972
Mill Creek219901989
Holcomb219911971
Compton219821972
Newark219731973
Sherburnvill219681968
Stillwell219941977
Cameron219941966
Monica219971984
Mackinaw219781978
Dailey219681968
Pawnee219851971
Kell220132002
Fairland219671967
Jamestown220021967
Birds219791976
Seneca219951995
Karnak220162001
Cave In Rock220211997
Guilford119901990
Atkinson119931966
Putnam119881988
Sheffield120142014

Loggerhead Shrike Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradofloridageorgiaidahoindianaiowakansaskentuckylouisianamainemarylandmichiganminnesotamississippimissourimontananebraskanevadanew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniasouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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