BirdAnalyst
Species · BCR 12 · BBS 2025 Release · 1966–2024

Brown-headed Cowbird In Boreal Hardwood Transition

All regionsBoreal Hardwood TransitionGeneralists

Brown-headed Cowbird in Boreal Hardwood Transition has collapsed: down 77% on the route-weighted index since 1968.

-77%Since 1968
125Routes In Region
58Years

Notable Signals

long arc declinecomputed index

Brown-headed Cowbird has collapsed in Boreal Hardwood Transition: down 77% on the route-weighted index since 1968.

Forecast

If the recent trend holds, Brown-headed Cowbird in Boreal Hardwood Transition is projected to fall about 100% by 2029 — from 2.7 in 2024 to a central estimate of 0.00 (95% range 0.00–3.3). A 5-year backtest shows a typical error of ±78%, with 100% of held-out values landing inside the 95% band.

-100%Change by 2029
0.00Projected 2029 index
0.00–3.395% range
±78%Backtest error
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 index95% low95% high
20250.560.003.9
20260.300.003.6
20270.040.003.3
20280.000.003.3
20290.000.003.3

Routes In Boreal Hardwood Transition

Routes recording Brown-headed Cowbird in Boreal Hardwood Transition.
BagleyMINNESOTA422006
Union TwpWISCONSIN232024
Traverse CtyMICHIGAN191992
Wigwam BayMINNESOTA192023
IronsMICHIGAN161989
BenaMINNESOTA151977
Pine RiverMINNESOTA132024
WausaukeeWISCONSIN132024
BrainerdMINNESOTA112024
BackusMINNESOTA102024
Rib LakeWISCONSIN102024
BashawWISCONSIN102023
IrmaWISCONSIN82024
CunardMICHIGAN72021
Cedar RunMICHIGAN71999
BemidjiMINNESOTA71980
ExelandWISCONSIN72024
RiggsvilleMICHIGAN62018
Walloon LakeMICHIGAN62004
FredericMICHIGAN62001
Frederic 2MICHIGAN62013
Island LakeMINNESOTA61995
Little ForkMINNESOTA62024
GreenbushMINNESOTA62024
ShanagoldenWISCONSIN62022

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