BirdAnalyst
Species · BCR 9 · BBS 2025 Release · 1966–2024

Loggerhead Shrike In Great Basin

All regionsGreat BasinGeneralists

Loggerhead Shrike in Great Basin has declined: down 35% on the route-weighted index since 1970.

-35%Since 1970TrendPercent 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 →
173Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 Loggerhead Shrike in Great Basin. See the full index history below.

Loggerhead Shrike In Great Basin Population Forecast

If the recent trend holds, Loggerhead Shrike in Great Basin is projected to fall about 40% by 2029 — from 1.6 in 2024 to a central estimate of 0.96 (95% range 0.30–1.6). A 5-year backtest shows a typical error of ±20%, with 80% of held-out values landing inside the 95% band.

-40%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 →
0.96Projected 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 →
0.30–1.695% 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 →
±20%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 Great Basin is projected to fall about 40% by 2029 — from 1.6 in 2024 to a central estimate of 0.96 (95% range 0.30–1.6). A 5-year backtest shows a typical error of ±20%, with 80% of held-out values landing inside the 95% band.19682029
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 →
20250.970.311.6
20260.960.311.6
20270.960.311.6
20280.960.301.6
20290.960.301.6

Routes In Great Basin

Routes recording Loggerhead Shrike in Great Basin.
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 →
Toiyabe NfNEVADA302024
GandyUTAH242015
SnowvilleUTAH182024
Harney LakeOREGON162024
RavendaleCALIFORNIA132024
Majors PlaceNEVADA132024
MikkaloOREGON112023
Malheur NwrOREGON92022
Johnson CanUTAH92022
CortezNEVADA82024
Bowden HillsOREGON82024
Arid Land ErWASHINGTON81996
Kyle CanyonIDAHO72024
MizpahNEVADA62024
MinervaNEVADA62024
Desert NwrNEVADA62024
Alvord LakeOREGON62024
Crooked Riv.OREGON62019
Trout CreekOREGON62021
PotholesWASHINGTON61997
Hot SpringIDAHO52014
Sand PassNEVADA52024
SutcliffeNEVADA51972
Ruby Valley 2NEVADA52024
Virgin CreekNEVADA52018

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