BirdAnalyst
Species · BCR 29 · BBS 2025 Release · 1966–2024

Brown-headed Cowbird In Piedmont

All regionsPiedmontGeneralists

Brown-headed Cowbird in Piedmont has held roughly steady: up 7% on the route-weighted index since 1968.

+7%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 →
170Routes 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 →

No notable trend signals for Brown-headed Cowbird in Piedmont. See the full index history below.

Brown-headed Cowbird In Piedmont Population Forecast

If the recent trend holds, Brown-headed Cowbird in Piedmont is projected to stay roughly flat through 2029, near 8.3 (95% range 6.5–10). A 5-year backtest shows a typical error of ±8.1%, with 100% of held-out values landing inside the 95% band.

-3%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 →
8.3Projected 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 →
6.5–1095% 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 →
±8.1%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 Piedmont is projected to stay roughly flat through 2029, near 8.3 (95% range 6.5–10). A 5-year backtest shows a typical error of ±8.1%, 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 →
20258.26.49.9
20268.26.410.0
20278.26.510.0
20288.36.510
20298.36.510

Routes In Piedmont

Routes recording Brown-headed Cowbird in Piedmont.
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 →
OlneyMARYLAND442024
West GrovePENNSYLVANIA281996
JacobusPENNSYLVANIA282024
EarltonMARYLAND262024
MadonnaMARYLAND252022
CrotonNEW-JERSEY212007
EkloMARYLAND202018
MonticelloNORTH-CAROLINA202024
Mount JoyPENNSYLVANIA192024
CandlerGEORGIA172024
IjamsvilleMARYLAND172024
ChathamPENNSYLVANIA162024
Nixburg 2ALABAMA152024
Good HopeGEORGIA152024
Rock BranchGEORGIA152024
EmmitsburgMARYLAND152024
FlayNORTH-CAROLINA152024
Little MtnSOUTH-CAROLINA151988
MillervilleALABAMA142024
OstwaltNORTH-CAROLINA142024
BendersvillePENNSYLVANIA142024
RinggoldVIRGINIA142024
WylliesburgVIRGINIA142019
WheatonMARYLAND132024
Croton 2NEW-JERSEY132024

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