BirdAnalyst
Species · BCR 35 · BBS 2025 Release · 1966–2024

Loggerhead Shrike In Chihuahuan Desert

All regionsChihuahuan DesertGeneralists

Loggerhead Shrike in Chihuahuan Desert has fallen sharply: down 52% on the route-weighted index since 1969.

-52%Since 1969TrendPercent 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 →
50Routes 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 →
57YearsYears 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 fallen sharply in Chihuahuan Desert: down 52% on the route-weighted index since 1969.

Loggerhead Shrike In Chihuahuan Desert Population Forecast

If the recent trend holds, Loggerhead Shrike in Chihuahuan Desert is projected to stay roughly flat through 2029, near 1.6 (95% range 0.00–4.3). A 5-year backtest shows a typical error of ±38.1%, with 100% of held-out values landing inside the 95% band.

-5%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 →
1.6Projected 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 →
0.00–4.395% 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 →
±38.1%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 Chihuahuan Desert is projected to stay roughly flat through 2029, near 1.6 (95% range 0.00–4.3). A 5-year backtest shows a typical error of ±38.1%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20251.90.004.5
20261.80.004.4
20271.70.004.4
20281.70.004.3
20291.60.004.3

Routes In Chihuahuan Desert

Routes recording Loggerhead Shrike in Chihuahuan Desert.
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 →
CornudasTEXAS112018
OzonaTEXAS102021
Chisos BasinTEXAS92019
RoswellNEW-MEXICO82023
LakewoodNEW-MEXICO82021
Sunshine WllNEW-MEXICO82024
CastolonTEXAS82019
San AntonioNEW-MEXICO71977
DemingNEW-MEXICO71975
Coyanda DrawTEXAS62024
MarathonTEXAS62023
Capitan Mtn.NEW-MEXICO52017
ColumbusNEW-MEXICO52024
Black GapTEXAS52022
ValentineTEXAS51987
Delaware CrkTEXAS52015
Bitter LakeNEW-MEXICO42023
Red RockNEW-MEXICO42023
Lake ValleyNEW-MEXICO42024
Van HornTEXAS42024
GageNEW-MEXICO32024
Quitman Canyon 2TEXAS32024
JornadaNEW-MEXICO22024
MesillaNEW-MEXICO22000
PinonNEW-MEXICO22017

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