BirdAnalyst
Species · BCR 16 · BBS 2025 Release · 1966–2024

Loggerhead Shrike In Southern Rockies / Colorado Plateau

All regionsSouthern Rockies / Colorado PlateauGeneralists

Loggerhead Shrike in Southern Rockies / Colorado Plateau has collapsed: down 78% on the route-weighted index since 1970.

-78%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 →
109Routes 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 →

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 Southern Rockies / Colorado Plateau: down 78% on the route-weighted index since 1970.

Loggerhead Shrike In Southern Rockies / Colorado Plateau Population Forecast

If the recent trend holds, Loggerhead Shrike in Southern Rockies / Colorado Plateau is projected to fall about 91% by 2029 — from 0.69 in 2024 to a central estimate of 0.06 (95% range 0.00–1.0). A 5-year backtest shows a typical error of ±75.3%, with 100% of held-out values landing inside the 95% band.

-91%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 →
0.06Projected 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 →
0.00–1.095% 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 →
±75.3%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 Southern Rockies / Colorado Plateau is projected to fall about 91% by 2029 — from 0.69 in 2024 to a central estimate of 0.06 (95% range 0.00–1.0). A 5-year backtest shows a typical error of ±75.3%, with 100% 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 →
20250.160.001.1
20260.140.001.1
20270.110.001.1
20280.090.001.1
20290.060.001.0

Routes In Southern Rockies / Colorado Plateau

Routes recording Loggerhead Shrike in Southern Rockies / Colorado Plateau.
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 →
JensenUTAH112024
ShivwitzUTAH112024
Salt Lake 2NEW-MEXICO82023
BlandingUTAH82024
SeligmanARIZONA72024
Sybille CynWYOMING72024
HuntARIZONA62018
WestwaterUTAH62024
BasinCOLORADO52024
CanyonlandsUTAH52024
Cane Spr DesUTAH52011
Lake PowellUTAH52009
Gilson Butte 2UTAH52018
KaibitoARIZONA42019
NageesiNEW-MEXICO42024
La Plata 2NEW-MEXICO42016
HanksvilleUTAH42024
EscalanteUTAH42024
The GapARIZONA31976
Cow SpringsARIZONA32017
CorreoNEW-MEXICO31982
CounselorNEW-MEXICO32023
Corona EastNEW-MEXICO31995
Salt LakeNEW-MEXICO32001
Willow CreekUTAH32024

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