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

Lesser Goldfinch In Sonoran and Mojave Deserts

All regionsSonoran and Mojave DesertsGeneralists

Lesser Goldfinch in Sonoran and Mojave Deserts has surged: up 87% on the route-weighted index since 1970.

+87%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 →
49Routes 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 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 →

Lesser Goldfinch has surged in Sonoran and Mojave Deserts: up 87% on the route-weighted index since 1970.

Forecast

If the recent trend holds, Lesser Goldfinch in Sonoran and Mojave Deserts is projected to fall about 20% by 2029 — from 0.80 in 2024 to a central estimate of 0.64 (95% range 0.04–1.2). A 5-year backtest shows a typical error of ±234.7%, with 80% of held-out values landing inside the 95% band.

-20%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 →
0.64Projected 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 →
0.04–1.295% 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 →
±234.7%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, Lesser Goldfinch in Sonoran and Mojave Deserts is projected to fall about 20% by 2029 — from 0.80 in 2024 to a central estimate of 0.64 (95% range 0.04–1.2). A 5-year backtest shows a typical error of ±234.7%, 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 →
20250.630.021.2
20260.630.021.2
20270.630.031.2
20280.640.031.2
20290.640.041.2

Routes In Sonoran and Mojave Deserts

Routes recording Lesser Goldfinch 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 →
BlytheCALIFORNIA272003
OatmanARIZONA142002
Lucerne ValCALIFORNIA92024
Havasu LakeCALIFORNIA92003
Red Rock 2ARIZONA82019
Cutter 2ARIZONA72018
Calif CityCALIFORNIA71980
ArabyARIZONA62023
Parker DamCALIFORNIA62007
PearblossomCALIFORNIA62024
LagunaARIZONA42021
Ajo 2ARIZONA42018
Haiwee ResCALIFORNIA41999
Kelso ValleyCALIFORNIA42024
Palo Verde 2ARIZONA32015
InyokernCALIFORNIA32021
Alamo RiverCALIFORNIA32017
Willow Springs 2CALIFORNIA32023
New RiverARIZONA22015
WildroseCALIFORNIA22005
Willow SpgsCALIFORNIA21974
BarstowCALIFORNIA21995
Anza BorregoCALIFORNIA22024
LenwoodCALIFORNIA21977
TecopaCALIFORNIA21993

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