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

Vesper Sparrow Population Trend in Arizona

All statesGrassland birds

Vesper Sparrow in Arizona has declined: down 43% on the route-weighted index since 1970.

-43%Since 1970
25Routes In State
50Years

Notable Vesper Sparrow Trends in Arizona

No notable trend signals for Vesper Sparrow in Arizona. See the full index history below.

Vesper Sparrow Population Forecast in Arizona

If the recent trend holds, Vesper Sparrow in Arizona is projected to fall about 21% by 2029 — from 0.43 in 2024 to a central estimate of 0.34 (95% range 0.00–2.3). A 5-year backtest shows a typical error of ±50.8%, with 100% of held-out values landing inside the 95% band.

-21%Change by 2029
0.34Projected 2029 index
0.00–2.395% range
±50.8%Backtest error
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 index95% low95% high
20250.420.002.4
20260.400.002.3
20270.380.002.3
20280.360.002.3
20290.340.002.3

Vesper Sparrow Survey Routes in Arizona

Routes recording Vesper Sparrow in Arizona.
Alpine1520231992
Black Mesa1419951989
Rose Wells1419781968
Yampai1219771975
Maine1220241992
Pinetop1120221993
Flagstaff920221988
House Rock519931976
Mormon Lake519751968
Clay Spring520211988
Round Rock419891969
Cow Springs420002000
Williams420192006
Navajo Trail420112011
Sprucedale420232003
Sawmill320101988
Castle Butte319941992
Happy Jack320241991
Tsaile220181993
Oraibi120181994
Hunt120061976
Blue119851976
Greasewood119951995
Forest Lakes120221994
Kaibito120101993

Vesper Sparrow Population Trend in Other States

californiacoloradoconnecticutdelawareidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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