BirdAnalyst
Species · BCR 27 · BBS 2025 Release · 1966–2024

Brown-headed Cowbird In Southeastern Coastal Plain

All regionsSoutheastern Coastal PlainGeneralists

Brown-headed Cowbird in Southeastern Coastal Plain has surged: up 134% on the route-weighted index since 1968.

+134%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 →
343Routes 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 →
58YearsYears 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 134% on the route-weighted index since 1968.

Forecast

If the recent trend holds, Brown-headed Cowbird in Southeastern Coastal Plain is projected to rise about 16% by 2029 — from 8.8 in 2024 to a central estimate of 10 (95% range 7.0–13). A 5-year backtest shows a typical error of ±20%, with 100% of held-out values landing inside the 95% band.

+16%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 →
10Projected 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 →
7.0–1395% 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 →
±20%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 rise about 16% by 2029 — from 8.8 in 2024 to a central estimate of 10 (95% range 7.0–13). A 5-year backtest shows a typical error of ±20%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20259.96.813
202610.06.813
2027106.913
2028107.013
2029107.013

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
MansfieldTENNESSEE592024
ElbertaALABAMA512022
TazewellGEORGIA452024
LovedaleFLORIDA372011
Duck HillMISSISSIPPI352024
Trace MadisonMISSISSIPPI312019
CockrumMISSISSIPPI302024
Trace LormanMISSISSIPPI302019
HumboldtTENNESSEE292024
Big SandyTENNESSEE262024
Rock ChapelALABAMA252024
Vicksburg NpMISSISSIPPI252021
Holly SpringsMISSISSIPPI242024
Maple HillNORTH-CAROLINA242023
BackbayVIRGINIA241974
TupeloMISSISSIPPI232022
LakeMISSISSIPPI222024
NewtonALABAMA212024
WrightsvilleGEORGIA212024
WorkmoreGEORGIA212019
DudleyNORTH-CAROLINA212024
BranchvilleVIRGINIA212024
EpesALABAMA202024
BostonGEORGIA202024

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