BirdAnalyst
Species · Arizona · BBS 2025 Release · 1966–2024

Brewer's Sparrow Population Trend in Arizona

All statesGeneralists

Brewer's Sparrow in Arizona has collapsed: down 78% on the route-weighted index since 1973.

-78%Since 1973
19Routes In State
47Years

Notable Brewer's Sparrow Trends in Arizona

long arc declinecomputed index

Brewer's Sparrow has collapsed in Arizona: down 78% on the route-weighted index since 1973.

Brewer's Sparrow Population Forecast in Arizona

If the recent trend holds, Brewer's Sparrow in Arizona is projected to rise about 63% by 2029 — from 0.06 in 2024 to a central estimate of 0.09 (95% range 0.00–1.4). A 5-year backtest shows a typical error of ±66.9%, with 100% of held-out values landing inside the 95% band.

+63%Change by 2029
0.09Projected 2029 index
0.00–1.495% range
±66.9%Backtest error
19692029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected index95% low95% high
20250.150.001.5
20260.140.001.5
20270.120.001.4
20280.110.001.4
20290.090.001.4

Brewer's Sparrow Survey Routes in Arizona

Routes recording Brewer's Sparrow in Arizona.
Pomerene1019741974
Sunizona919881974
House Rock820211971
Mt Trumbull619801977
Black Mesa619951988
Navajo Trail620231995
The Gap419731973
Toroweap320231995
Alamo Res.319921992
Oraibi220192018
Page220191995
Round Rock119691969
Sawmill119961990
Cow Springs120222019
Antares120242004
Skull Valley120212021
Pinetop120181993
Tsaile120192018
Clay Spring120241989

Brewer's Sparrow Population Trend in Other States

californiacoloradoidahokansasmontananebraskanevadanew-mexiconorth-dakotaoklahomaoregonsouth-dakotatexasutahwashingtonwyoming

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