BirdAnalyst
Species · BBS 2026 Release · 1966–2025

Rufous-crowned Sparrow Population Analysis

PasserellidaeArid-land birdsAimophila ruficeps

Rufous-crowned Sparrow has surged: up 95% on the route-weighted index since 1969.

+95%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 →
227RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Rufous-crowned Sparrow

The Rufous-crowned Sparrow (Aimophila ruficeps) is a North American member of the New World Sparrows (Passerellidae). In this analysis it is grouped with the arid-land birds.

Size
4.5–7.5 in long (12–19 cm) — a small songbird (typical for the family)
Habitat
Deserts, dry scrub and brushland of the Southwest.
Diet
Seeds, insects and cactus fruit of arid-land plants.
Range
Recorded on 227 Breeding Bird Survey routes across 9 states, most concentrated in the Coastal California.
Family
Passerellidae · Arid-land birds

Notable Rufous-crowned Sparrow TrendsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Rufous-crowned Sparrow. See the full index history below.

Rufous-crowned Sparrow Population Forecast

If the recent trend holds, Rufous-crowned Sparrow is projected to rise about 37% by 2030 — from 0.08 in 2025 to a central estimate of 0.11 (95% range 0.06–0.17). A 5-year backtest shows a typical error of ±39.2%, with 100% of held-out values landing inside the 95% band.

+37%Change by 2030TrendPercent 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 →
0.11Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.06–0.1795% 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 →
±39.2%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 is projected to rise about 37% by 2030 — from 0.08 in 2025 to a central estimate of 0.11 (95% range 0.06–0.17). A 5-year backtest shows a typical error of ±39.2%, with 100% of held-out values landing inside the 95% band.19672030
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 →
20260.110.060.16
20270.110.060.16
20280.110.060.17
20290.110.060.17
20300.110.060.17

Where the Rufous-crowned Sparrow Is Detected

BBS routes recording Rufous-crowned Sparrow, sized by most recent count.

Rufous-crowned Sparrow Population Trend by State

Rufous-crowned Sparrow population trend by state.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Arizona+272%197034
California+382%197274
Coloradoinsufficient datan/a1
Montanainsufficient datan/a1
Nevadainsufficient datan/a1
New Mexico+40%197028
Oklahoma+491%196910
Texas-26%196976
Utahinsufficient datan/a2

Rufous-crowned Sparrow Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Rufous-crowned Sparrow population trend by Bird Conservation Region.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Sierra Nevada+12%19976
Southern Rockies / Colorado Plateau-93%198812
Shortgrass Prairie-81%197014
Central Mixed Grass Prairie+439%197018
Edwards Plateau-3%197018
Oaks and Prairies-93%196914
Coastal California+522%197263
Sonoran and Mojave Deserts+173%19918
Sierra Madre Occidental+118%197028
Chihuahuan Desert+66%196935

Rufous-crowned Sparrow Conservation Status

Our route-weighted index shows it up about 95% since 1969.

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14. Trend is a route-weighted relative-abundance index, not an absolute population.