BirdAnalyst
Species · BCR 23 · BBS 2025 Release · 1966–2024

Brewer's Blackbird In Prairie Hardwood Transition

All regionsPrairie Hardwood TransitionGeneralists

Brewer's Blackbird in Prairie Hardwood Transition has collapsed: down 79% on the route-weighted index since 1968.

-79%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 →
65Routes 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 →

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 79% 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 63% by 2029 — from 0.28 in 2024 to a central estimate of 0.45 (95% range 0.00–1.6). A 5-year backtest shows a typical error of ±159.7%, with 100% of held-out values landing inside the 95% band.

+63%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 →
0.45Projected 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 →
0.00–1.695% 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 →
±159.7%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 63% by 2029 — from 0.28 in 2024 to a central estimate of 0.45 (95% range 0.00–1.6). A 5-year backtest shows a typical error of ±159.7%, 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 →
20250.570.001.7
20260.540.001.7
20270.510.001.6
20280.480.001.6
20290.450.001.6

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
StratfordWISCONSIN92013
MinnetonkaMINNESOTA81996
OsseoMINNESOTA82017
EvergreenMINNESOTA82024
MerrillWISCONSIN82015
StetsonvilleWISCONSIN82024
Money CreekMINNESOTA71998
AshbyMINNESOTA72021
ManawaWISCONSIN62014
Mount HorebWISCONSIN61970
Buena VistaWISCONSIN62024
KnappMINNESOTA52002
CumberlandWISCONSIN52018
ViroquaWISCONSIN51976
PrincetonWISCONSIN51993
New TroyMICHIGAN41972
MillvilleMINNESOTA42019
HolwayWISCONSIN41989
GilmantonWISCONSIN41988
UnityWISCONSIN42023
PardeevilleWISCONSIN42022
MerideanWISCONSIN42019
GreshamWISCONSIN42011
CaledoniaMINNESOTA31996

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