BirdAnalyst
Species · Maine · BBS 2025 Release · 1966–2024

Brown-headed Cowbird Population Trend in Maine

All statesGeneralists

Brown-headed Cowbird in Maine has collapsed: down 81% on the route-weighted index since 1968.

-81%Since 1968
68Routes In State
58Years

Notable Brown-headed Cowbird Trends in Maine

long arc declinecomputed index

Brown-headed Cowbird has collapsed in Maine: down 81% on the route-weighted index since 1968.

Brown-headed Cowbird Population Forecast in Maine

If the recent trend holds, Brown-headed Cowbird in Maine is projected to fall about 100% by 2029 — from 1.9 in 2024 to a central estimate of 0.00 (95% range 0.00–2.4). A 5-year backtest shows a typical error of ±150.6%, with 60% of held-out values landing inside the 95% band.

-100%Change by 2029
0.00Projected 2029 index
0.00–2.495% range
±150.6%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
20250.000.002.4
20260.000.002.4
20270.000.002.4
20280.000.002.4
20290.000.002.4

Brown-headed Cowbird Survey Routes in Maine

Routes recording Brown-headed Cowbird in Maine.
Benton2219801972
Warren1019901973
Kittery Pt920241966
Manchester919951971
Otisfield Gr820151966
Topsfield719961978
Cape Neddick620241972
Turner520101972
Northfield519811976
Turner 2520242012
Freedom420211973
Harmony420241967
Carrying Pl420021980
Washburn420051979
Ft Fairfield420051993
St David420051982
Westbrook320241977
Biddeford320191974
Bowdoin Ctr320211971
Hancock320121969
Winn320181969
Clayton Lake319771977
Cornville320242012
Searsport320242002
Church Hill320141991

Brown-headed Cowbird Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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