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

Brown-headed Cowbird Population Trend in Arizona

All statesGeneralists

Brown-headed Cowbird in Arizona has fallen sharply: down 56% on the route-weighted index since 1970.

-56%Since 1970
88Routes In State
56Years

Notable Brown-headed Cowbird Trends in Arizona

long arc declinecomputed index

Brown-headed Cowbird has fallen sharply in Arizona: down 56% on the route-weighted index since 1970.

Brown-headed Cowbird Population Forecast in Arizona

If the recent trend holds, Brown-headed Cowbird in Arizona is projected to stay roughly flat through 2029, near 4.7 (95% range 0.00–11). A 5-year backtest shows a typical error of ±31.5%, with 100% of held-out values landing inside the 95% band.

+9%Change by 2029
4.7Projected 2029 index
0.00–1195% range
±31.5%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
20255.00.0012
20265.00.0012
20274.90.0011
20284.80.0011
20294.70.0011

Brown-headed Cowbird Survey Routes in Arizona

Routes recording Brown-headed Cowbird in Arizona.
Pomerene3020241968
Amado2820231993
Happy Jack1920241977
Bartlett Res1720241993
Ajo1620011968
Cactus Forest1520241991
Patagonia1420241968
Palo Verde1220131992
Dragoon1220091995
Pinetop1120221993
Cutter1120141992
Pisinimo1119931992
Mormon Lake1019741968
Redington1020231993
The Gap919761968
Prescott820221974
Laguna720231968
Williams720181993
Araby720231992
Dateland620241990
Skull Valley620241996
Wickenburg620232017
Peach Spring620241993
House Rock520211968
Hunt520051968

Brown-headed Cowbird Population Trend in Other States

alabamaalaskaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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