BirdAnalyst
Species · BCR 5 · BBS 2026 Release · 1966–2025

Brown-headed Cowbird In Northern Pacific Rainforest

All regionsNorthern Pacific RainforestGeneralists

Brown-headed Cowbird in Northern Pacific Rainforest has fallen sharply: down 74% on the route-weighted index since 1970.

-74%Since 1970TrendPercent 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 →
112Routes 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 →
57YearsYears 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 declinecomputed 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 fallen sharply in Northern Pacific Rainforest: down 74% on the route-weighted index since 1970.

Brown-headed Cowbird In Northern Pacific Rainforest Population Forecast

If the recent trend holds, Brown-headed Cowbird in Northern Pacific Rainforest is projected to fall about 69% by 2030 — from 4.1 in 2025 to a central estimate of 1.3 (95% range 0.00–4.6). A 5-year backtest shows a typical error of ±57.4%, with 100% of held-out values landing inside the 95% band.

-69%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 →
1.3Projected 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 →
0.00–4.695% 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 →
±57.4%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 Northern Pacific Rainforest is projected to fall about 69% by 2030 — from 4.1 in 2025 to a central estimate of 1.3 (95% range 0.00–4.6). A 5-year backtest shows a typical error of ±57.4%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20261.80.005.1
20271.60.005.0
20281.50.004.8
20291.40.004.7
20301.30.004.6

Routes In Northern Pacific Rainforest

Routes recording Brown-headed Cowbird in Northern Pacific Rainforest.
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 →
Port AngelesWASHINGTON372025
Horse CreekCALIFORNIA202019
YrekaCALIFORNIA172019
GlasgowOREGON162025
DaytonOREGON152025
RainierWASHINGTON142025
EverettWASHINGTON132025
Crescent CtyCALIFORNIA122025
CanbyOREGON122025
Mendota 3WASHINGTON122025
South ElmaWASHINGTON112024
Bay ViewWASHINGTON112017
ElktonOREGON102025
Emigrant LkOREGON102001
Nicolai Mtn.OREGON102025
GreenOREGON102025
ScappooseOREGON102025
IssaquahWASHINGTON101987
HoneydewCALIFORNIA92017
SvensenOREGON91992
SalemOREGON92025
MendotaWASHINGTON91988
Rio DellCALIFORNIA82011
AlderpointCALIFORNIA82012
AdairOREGON82025

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