BirdAnalyst
Species · BCR 23 · BBS 2026 Release · 1966–2025

Brewer's Blackbird In Prairie Hardwood Transition

All regionsPrairie Hardwood TransitionGeneralists

Brewer's Blackbird in Prairie Hardwood Transition has collapsed: down 83% on the route-weighted index since 1968.

-83%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 →
66Routes 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 →

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 →

Brewer's Blackbird has collapsed in Prairie Hardwood Transition: down 83% on the route-weighted index since 1968.

Brewer's Blackbird In Prairie Hardwood Transition Population Forecast

If the recent trend holds, Brewer's Blackbird in Prairie Hardwood Transition is projected to rise about 82% by 2030 — from 0.21 in 2025 to a central estimate of 0.39 (95% range 0.00–1.5). A 5-year backtest shows a typical error of ±166.7%, with 100% of held-out values landing inside the 95% band.

+82%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 →
0.39Projected 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 →
0.00–1.595% 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 →
±166.7%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, Brewer's Blackbird in Prairie Hardwood Transition is projected to rise about 82% by 2030 — from 0.21 in 2025 to a central estimate of 0.39 (95% range 0.00–1.5). A 5-year backtest shows a typical error of ±166.7%, 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 →
20260.510.001.6
20270.480.001.6
20280.450.001.6
20290.420.001.5
20300.390.001.5

Routes In Prairie Hardwood Transition

Routes recording Brewer's Blackbird in Prairie Hardwood Transition.
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 →
LoraineWISCONSIN222005
EvergreenMINNESOTA102025
StratfordWISCONSIN92013
MinnetonkaMINNESOTA81996
OsseoMINNESOTA82017
MerrillWISCONSIN82015
StetsonvilleWISCONSIN82024
Money CreekMINNESOTA71998
AshbyMINNESOTA72021
MillvilleMINNESOTA62025
ManawaWISCONSIN62014
Mount HorebWISCONSIN61970
KnappMINNESOTA52002
CumberlandWISCONSIN52018
ViroquaWISCONSIN51976
PrincetonWISCONSIN51993
New TroyMICHIGAN41972
HolwayWISCONSIN41989
GilmantonWISCONSIN41988
UnityWISCONSIN42023
MerideanWISCONSIN42019
GreshamWISCONSIN42011
CaledoniaMINNESOTA31996
EsdaileWISCONSIN31977
CochraneWISCONSIN31999

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