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

Loggerhead Shrike Population Trend in Utah

All statesGeneralists

Loggerhead Shrike in Utah has surged: up 105% on the route-weighted index since 1971.

+105%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 →
74Routes 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 →
49YearsYears 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 UtahNotable 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 Utah: up 105% on the route-weighted index since 1971.

Loggerhead Shrike Population Forecast in Utah

If the recent trend holds, Loggerhead Shrike in Utah is projected to fall about 29% by 2029 — from 1.6 in 2024 to a central estimate of 1.2 (95% range 0.61–1.7). A 5-year backtest shows a typical error of ±17.7%, with 80% of held-out values landing inside the 95% band.

-29%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 →
1.2Projected 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 →
0.61–1.795% 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 →
±17.7%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, Loggerhead Shrike in Utah is projected to fall about 29% by 2029 — from 1.6 in 2024 to a central estimate of 1.2 (95% range 0.61–1.7). A 5-year backtest shows a typical error of ±17.7%, with 80% 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 →
20251.10.581.7
20261.10.591.7
20271.20.601.7
20281.20.601.7
20291.20.611.7

Loggerhead Shrike Survey Routes in Utah

Routes recording Loggerhead Shrike in Utah.
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 →
Gandy2420151997
Snowville1820241999
Shivwitz1120241993
Jensen1120241992
Johnson Can920221988
Blanding820241987
Westwater620241998
Promontory520241969
Gilson Butte 2520182006
Leamington520171992
Lake Powell520091998
Canyonlands520241986
Cane Spr Des520111993
Stock Res420041986
Hanksville420241994
Tule Valley420121999
Escalante420241999
Wah Wah420151990
Willow Creek320241986
Hite320231992
Kelton319951992
Callao320241997
Jericho Junction320231997
Green River320091999
Peplin Mountain320241999

Loggerhead Shrike Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradofloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmichiganminnesotamississippimissourimontananebraskanevadanew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniasouth-carolinasouth-dakotatennesseetexasvermontvirginiawashingtonwest-virginiawisconsinwyoming

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