BirdAnalyst
Species · BCR 9 · BBS 2025 Release · 1966–2024

Brown-headed Cowbird In Great Basin

All regionsGreat BasinGeneralists

Brown-headed Cowbird in Great Basin has edged up: up 19% on the route-weighted index since 1970.

+19%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 →
256Routes 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 →
56YearsYears 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 Great Basin. See the full index history below.

Brown-headed Cowbird In Great Basin Population Forecast

If the recent trend holds, Brown-headed Cowbird in Great Basin is projected to rise about 45% by 2029 — from 5.4 in 2024 to a central estimate of 7.9 (95% range 2.9–13). A 5-year backtest shows a typical error of ±64.2%, with 100% of held-out values landing inside the 95% band.

+45%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 →
7.9Projected 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 →
2.9–1395% 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 →
±64.2%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 Great Basin is projected to rise about 45% by 2029 — from 5.4 in 2024 to a central estimate of 7.9 (95% range 2.9–13). A 5-year backtest shows a typical error of ±64.2%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20258.02.913
20268.02.913
20277.92.913
20287.92.913
20297.92.913

Routes In Great Basin

Routes recording Brown-headed Cowbird in Great Basin.
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 →
DorrisCALIFORNIA2002019
UmatillaOREGON1152023
OthelloWASHINGTON521991
TwispWASHINGTON492024
NighthawkWASHINGTON422024
CedarvilleCALIFORNIA302024
Lake ChelanWASHINGTON292024
Columbia NwrWASHINGTON292022
Iron GateCALIFORNIA282019
Glenns FerryIDAHO271986
MesaWASHINGTON272008
IngallsCALIFORNIA252001
LeavenworthWASHINGTON252024
Ruby ValleyNEVADA242001
NewcastleUTAH242022
ArdenvoirWASHINGTON231987
KendallWASHINGTON232024
Mt HoodOREGON222024
Modoc Point 2OREGON222024
HarringtonWASHINGTON222012
Crowder FlatCALIFORNIA212019
Fandango CanOREGON212024
PicaboIDAHO202021
GardnervilleNEVADA192012
BuchananOREGON192024

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