BirdAnalyst
Species · BCR 13 · BBS 2026 Release · 1966–2025

Brown-headed Cowbird In Lower Great Lakes / St. Lawrence Plain

All regionsLower Great Lakes / St. Lawrence PlainGeneralists

Brown-headed Cowbird in Lower Great Lakes / St. Lawrence Plain has declined: down 36% on the route-weighted index since 1968.

-36%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 →
86Routes 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 →

No notable trend signals for Brown-headed Cowbird in Lower Great Lakes / St. Lawrence Plain. See the full index history below.

Brown-headed Cowbird In Lower Great Lakes / St. Lawrence Plain Population Forecast

If the recent trend holds, Brown-headed Cowbird in Lower Great Lakes / St. Lawrence Plain is projected to fall about 23% by 2030 — from 9.5 in 2025 to a central estimate of 7.3 (95% range 4.6–10.0). A 5-year backtest shows a typical error of ±15.4%, with 100% of held-out values landing inside the 95% band.

-23%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 →
7.3Projected 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 →
4.6–10.095% 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 →
±15.4%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 Lower Great Lakes / St. Lawrence Plain is projected to fall about 23% by 2030 — from 9.5 in 2025 to a central estimate of 7.3 (95% range 4.6–10.0). A 5-year backtest shows a typical error of ±15.4%, 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 →
20267.64.910
20277.64.810
20287.54.710
20297.44.710
20307.34.610.0

Routes In Lower Great Lakes / St. Lawrence Plain

Routes recording Brown-headed Cowbird in Lower Great Lakes / St. Lawrence 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 →
CayugaNEW-YORK432025
Ballston LkNEW-YORK251995
MacdougallNEW-YORK242025
ChurchvilleNEW-YORK232025
OrleansNEW-YORK222025
West BangorNEW-YORK201998
E YoungstownNEW-YORK182025
Valley CityOHIO182025
Mt MorrisNEW-YORK172025
Harris HillNEW-YORK172025
NashvilleNEW-YORK162018
NaplesNEW-YORK162025
West SenecaNEW-YORK152004
PenfieldNEW-YORK152025
MaysvilleOHIO152012
New SomersetOHIO151993
Cicero CtrNEW-YORK132025
PittsfieldOHIO132024
HiramOHIO132025
RomulusNEW-YORK122000
HamburgNEW-YORK122025
N VictoryNEW-YORK121972
LenoxOHIO122025
LattasburgOHIO122025
CatskillsNEW-YORK112015

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