BirdAnalyst
Species · BCR 37 · BBS 2026 Release · 1966–2025

Bronzed Cowbird In Gulf Coastal Prairie

All regionsGulf Coastal PrairieGeneralists

Bronzed Cowbird in Gulf Coastal Prairie has surged: up 102% on the route-weighted index since 1971.

+102%Since 1971TrendPercent 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 →
16Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
52YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 increasecomputed 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 surged in Gulf Coastal Prairie: up 102% on the route-weighted index since 1971.

Bronzed Cowbird In Gulf Coastal Prairie Population Forecast

If the recent trend holds, Bronzed Cowbird in Gulf Coastal Prairie is projected to rise about 13% by 2030 — from 4.3 in 2025 to a central estimate of 4.8 (95% range 1.1–8.5). A 5-year backtest shows a typical error of ±53.5%, with 100% of held-out values landing inside the 95% band.

+13%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 →
4.8Projected 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 →
1.1–8.595% 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 →
±53.5%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 Gulf Coastal Prairie is projected to rise about 13% by 2030 — from 4.3 in 2025 to a central estimate of 4.8 (95% range 1.1–8.5). A 5-year backtest shows a typical error of ±53.5%, with 100% of held-out values landing inside the 95% band.19692030
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 →
20264.60.928.3
20274.70.978.4
20284.71.08.4
20294.81.18.5
20304.81.18.5

Routes In Gulf Coastal Prairie

Routes recording Bronzed Cowbird in Gulf Coastal Prairie.
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 →
L. Atascosa NwrTEXAS652025
Loyola BeachTEXAS402009
Loyola Beach 2TEXAS172025
San PedroTEXAS142023
Lag AtascosaTEXAS92025
GlencoeLOUISIANA82011
BaysideTEXAS42010
Bayside 2TEXAS42004
Bayside 3TEXAS22025
LafitteLOUISIANA11990
Grand IsleLOUISIANA12018
PetronilaTEXAS12025
IndianolaTEXAS12023
WinnieTEXAS12015
Goliad PrairieTEXAS12015
McfaddinTEXAS12009

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.