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

Bronzed Cowbird Population Trend in Arizona

All statesGeneralists

Bronzed Cowbird in Arizona has collapsed: down 80% on the route-weighted index since 1970.

-80%Since 1970TrendPercent 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 →
29Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Bronzed Cowbird Trends in ArizonaNotable 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 declinecomputed 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 →

Bronzed Cowbird has collapsed in Arizona: down 79% on the route-weighted index since 1970.

Bronzed Cowbird Population Forecast in Arizona

If the recent trend holds, Bronzed Cowbird in Arizona is projected to fall about 100% by 2029 — from 0.06 in 2024 to a central estimate of 0.00 (95% range 0.00–0.93). A 5-year backtest shows a typical error of ±115.7%, with 100% of held-out values landing inside the 95% band.

-100%Change by 2029TrendPercent 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 →
0.00Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.9395% 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 →
±115.7%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, Bronzed Cowbird in Arizona is projected to fall about 100% by 2029 — from 0.06 in 2024 to a central estimate of 0.00 (95% range 0.00–0.93). A 5-year backtest shows a typical error of ±115.7%, with 100% of held-out values landing inside the 95% band.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 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 →
20250.000.000.93
20260.000.000.93
20270.000.000.93
20280.000.000.93
20290.000.000.93

Bronzed Cowbird Survey Routes in Arizona

Routes recording Bronzed Cowbird in Arizona.
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 →
Florence919881970
Ajo820011968
New River420141977
Bartlett Res420212006
Casa Grande420091989
Portal320231977
San Simon319801974
Sunizona319861970
Rucker219971997
Pomerene220231968
Patagonia220241969
Cutter 2220172016
Organ Pipe119941994
Dragoon120021995
Prescott119991980
Laguna120081968
Lukeville119801977
Peña Blanca120011975
Skull Valley120212014
Araby120102006
Redington120061994
Amado120231993
Sahuarita120071992
Mcneal120011997
Wickenburg120212017

Bronzed Cowbird Population Trend in Other States

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