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

Rufous-crowned Sparrow In Sonoran and Mojave Deserts

All regionsSonoran and Mojave DesertsGeneralists

Rufous-crowned Sparrow in Sonoran and Mojave Deserts has surged: up 173% on the route-weighted index since 1991.

+173%Since 1991TrendPercent 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 →
8Routes 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 →
27YearsYears 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 →

Rufous-crowned Sparrow has surged in Sonoran and Mojave Deserts: up 173% on the route-weighted index since 1991.

Rufous-crowned Sparrow In Sonoran and Mojave Deserts Population Forecast

If the recent trend holds, Rufous-crowned Sparrow in Sonoran and Mojave Deserts is projected to fall about 43% by 2028 — from 0.33 in 2023 to a central estimate of 0.19 (95% range 0.04–0.34). A 5-year backtest shows a typical error of ±66.3%, with 80% of held-out values landing inside the 95% band.

-43%Change by 2028TrendPercent 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 →
0.19Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.04–0.3495% 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 →
±66.3%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, Rufous-crowned Sparrow in Sonoran and Mojave Deserts is projected to fall about 43% by 2028 — from 0.33 in 2023 to a central estimate of 0.19 (95% range 0.04–0.34). A 5-year backtest shows a typical error of ±66.3%, with 80% of held-out values landing inside the 95% band.19732028
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 →
20240.180.030.32
20250.180.030.33
20260.180.040.33
20270.190.040.34
20280.190.040.34

Routes In Sonoran and Mojave Deserts

Routes recording Rufous-crowned Sparrow 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 →
WickenburgARIZONA92023
OatmanARIZONA22006
Joshua TreeCALIFORNIA21997
Alamo Res.ARIZONA12023
Palo VerdeARIZONA12004
Casa GrandeARIZONA12016
Cutter 2ARIZONA12018
OnyxCALIFORNIA11997

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