BirdAnalyst
Species · BCR 27 · BBS 2026 Release · 1966–2025

Brown-headed Cowbird In Southeastern Coastal Plain

All regionsSoutheastern Coastal PlainGeneralists

Brown-headed Cowbird in Southeastern Coastal Plain has surged: up 148% on the route-weighted index since 1968.

+148%Since 1968TrendPercent 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 →
344Routes 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 →
59YearsYears 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 →

Brown-headed Cowbird has surged in Southeastern Coastal Plain: up 148% on the route-weighted index since 1968.

Brown-headed Cowbird In Southeastern Coastal Plain Population Forecast

If the recent trend holds, Brown-headed Cowbird in Southeastern Coastal Plain is projected to stay roughly flat through 2030, near 10 (95% range 7.2–13). A 5-year backtest shows a typical error of ±16.2%, with 100% of held-out values landing inside the 95% band.

-2%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 →
10Projected 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 →
7.2–1395% 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 →
±16.2%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, Brown-headed Cowbird in Southeastern Coastal Plain is projected to stay roughly flat through 2030, near 10 (95% range 7.2–13). A 5-year backtest shows a typical error of ±16.2%, with 100% of held-out values landing inside the 95% band.19662030
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 →
202610.06.913
2027107.013
2028107.013
2029107.113
2030107.213

Routes In Southeastern Coastal Plain

Routes recording Brown-headed Cowbird in Southeastern Coastal Plain.
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 →
MashoesNORTH-CAROLINA691982
ShilohGEORGIA532025
MansfieldTENNESSEE532025
ElbertaALABAMA512022
NewtonGEORGIA482025
HowardALABAMA462025
LovedaleFLORIDA372011
HumboldtTENNESSEE342025
Trace MadisonMISSISSIPPI312019
CockrumMISSISSIPPI302024
Trace LormanMISSISSIPPI302019
Big SandyTENNESSEE302025
CalebeeALABAMA292025
Rock ChapelALABAMA252024
FinleysonGEORGIA252025
Vicksburg NpMISSISSIPPI252021
Cypress LakesNORTH-CAROLINA252025
Duck HillMISSISSIPPI242025
Holly SpringsMISSISSIPPI242024
Maple HillNORTH-CAROLINA242023
BackbayVIRGINIA241974
JenaALABAMA232025
CarrolltonALABAMA232025
CottonGEORGIA232025
TupeloMISSISSIPPI232022

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