BirdAnalyst
Species · BCR 33 · BBS 2025 Release · 1966–2024

LeConte's Thrasher In Sonoran and Mojave Deserts

All regionsSonoran and Mojave DesertsGeneralists

LeConte's Thrasher in Sonoran and Mojave Deserts has collapsed: down 97% on the route-weighted index since 1970.

-97%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 →
56Routes 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 →

LeConte's Thrasher has collapsed in Sonoran and Mojave Deserts: down 97% on the route-weighted index since 1970.

Forecast

If the recent trend holds, LeConte's Thrasher in Sonoran and Mojave Deserts is projected to fall about 100% by 2029 — from 0.10 in 2024 to a central estimate of 0.00 (95% range 0.00–1.4). A 5-year backtest shows a typical error of ±267.9%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–1.495% 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 →
±267.9%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, LeConte's Thrasher in Sonoran and Mojave Deserts is projected to fall about 100% by 2029 — from 0.10 in 2024 to a central estimate of 0.00 (95% range 0.00–1.4). A 5-year backtest shows a typical error of ±267.9%, 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 →
20250.000.001.4
20260.000.001.4
20270.000.001.4
20280.000.001.4
20290.000.001.4

Routes In Sonoran and Mojave Deserts

Routes recording LeConte's Thrasher in Sonoran and Mojave Deserts.
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 →
Willow SpgsCALIFORNIA131981
GoldstoneCALIFORNIA92009
Valley WellsCALIFORNIA52023
IvanpahCALIFORNIA52019
DatelandARIZONA42012
Iron MtnsCALIFORNIA42017
Death ValleyCALIFORNIA41995
VicksburgARIZONA31989
Cibola LakeARIZONA31994
WildroseCALIFORNIA32022
BarstowCALIFORNIA31996
Havasu LakeCALIFORNIA31973
CottonwoodCALIFORNIA32019
BlytheCALIFORNIA31973
CadizCALIFORNIA21988
LenwoodCALIFORNIA21993
Lone PineCALIFORNIA22024
Joshua TreeCALIFORNIA22000
Joshua Tree 2CALIFORNIA22013
Ash MeadowsNEVADA22019
OatmanARIZONA11988
QuartzsiteARIZONA11979
LagunaARIZONA12003
AjoARIZONA12001
CoolidgeARIZONA11974

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