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

Cape May Warbler Population Trend in Michigan

All statesForest birds

Cape May Warbler in Michigan has held roughly steady: down 1% on the route-weighted index since 1978.

-1%Since 1978TrendPercent 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 →
34Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
44YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Cape May Warbler Trends in MichiganNotable 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 Cape May Warbler in Michigan. See the full index history below.

Cape May Warbler Population Forecast in Michigan

If the recent trend holds, Cape May Warbler in Michigan is projected to stay roughly flat through 2029, near 0.22 (95% range 0.00–0.44). A 5-year backtest shows a typical error of ±100.6%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.22Projected 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 →
0.00–0.4495% 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 →
±100.6%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, Cape May Warbler in Michigan is projected to stay roughly flat through 2029, near 0.22 (95% range 0.00–0.44). A 5-year backtest shows a typical error of ±100.6%, with 100% of held-out values landing inside the 95% band.19752029
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 →
20250.210.000.44
20260.210.000.44
20270.210.000.44
20280.220.000.44
20290.220.000.44

Cape May Warbler Survey Routes in Michigan

Routes recording Cape May Warbler in Michigan.
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 →
Imp Lake520161992
Herman420222015
Ishpeming420211980
Cathro419951988
Ontonagon220181975
Bergland220221989
Cunard219941983
Shingleton220231979
Seney Nwr220141996
Mayfield220052005
Isabella 2220192019
Marenisco120161981
Bootjack120231992
Ned Lake120101988
Crystal Fls120241989
Gibbs City120231982
Maple Grove120231980
Brocky Lake120231980
Wilson119821982
Creighton119811978
Isabella119951982
Sidnaw120231996
Ensign120092007
Muskallonge120241977
Tahquamenon120231994

Cape May Warbler Population Trend in Other States

maineminnesotanew-hampshirenew-yorkvermontwisconsin

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