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

Loggerhead Shrike Population Trend in Idaho

All statesGeneralists

Loggerhead Shrike in Idaho has surged: up 142% on the route-weighted index since 1971.

+142%Since 1971TrendPercent 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 →
23Routes 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 →
53YearsYears 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 IdahoNotable 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 →

Loggerhead Shrike has surged in Idaho: up 142% on the route-weighted index since 1971.

Loggerhead Shrike Population Forecast in Idaho

If the recent trend holds, Loggerhead Shrike in Idaho is projected to fall about 19% by 2029 — from 0.68 in 2024 to a central estimate of 0.55 (95% range 0.03–1.1). A 5-year backtest shows a typical error of ±103.3%, with 100% of held-out values landing inside the 95% band.

-19%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 →
0.55Projected 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 →
0.03–1.195% 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 →
±103.3%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 Idaho is projected to fall about 19% by 2029 — from 0.68 in 2024 to a central estimate of 0.55 (95% range 0.03–1.1). A 5-year backtest shows a typical error of ±103.3%, with 100% of held-out values landing inside the 95% band.19692029
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 →
20250.540.021.1
20260.540.021.1
20270.550.031.1
20280.550.031.1
20290.550.031.1

Loggerhead Shrike Survey Routes in Idaho

Routes recording Loggerhead Shrike in Idaho.
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 →
Kyle Canyon720241985
Hot Spring520141988
Tractor Flat420241985
Almo420232015
Twin Buttes320241985
Picabo320181988
Craters220171980
Acequia220071979
Pasadena Val220072003
Lost River120241987
Circular Bu120241985
Dubois120241969
Springfield119801976
Triangle120151992
Henry119811981
Joel119921990
Crane Creek120191992
Silver City120181994
Carey120171990
Mud Lake120042004
Dougal Res120151990
Cedar Hill120231993
Daniels Res120002000

Loggerhead Shrike Population Trend in Other States

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

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