BirdAnalyst
Species · BCR 14 · BBS 2025 Release · 1966–2024

Cape May Warbler In Atlantic Northern Forest

All regionsAtlantic Northern ForestForest birds

Cape May Warbler in Atlantic Northern Forest has fallen sharply: down 54% on the route-weighted index since 1969.

-54%Since 1969TrendPercent 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 →
84Routes 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 →
55YearsYears 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 →

Cape May Warbler has fallen sharply in Atlantic Northern Forest: down 54% on the route-weighted index since 1969.

Cape May Warbler In Atlantic Northern Forest Population Forecast

If the recent trend holds, Cape May Warbler in Atlantic Northern Forest is projected to stay roughly flat through 2028, near 0.08 (95% range 0.00–0.26). A 5-year backtest shows a typical error of ±89.3%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2028TrendPercent 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 →
0.08Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.2695% 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 →
±89.3%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 Atlantic Northern Forest is projected to stay roughly flat through 2028, near 0.08 (95% range 0.00–0.26). A 5-year backtest shows a typical error of ±89.3%, with 100% of held-out values landing inside the 95% band.19672028
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 →
20240.090.000.27
20250.080.000.27
20260.080.000.27
20270.080.000.27
20280.080.000.26

Routes In Atlantic Northern Forest

Routes recording Cape May Warbler in Atlantic Northern Forest.
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 →
Pillsbury PdMAINE81968
BaxterMAINE61984
NorthfieldMAINE41981
Clayton LakeMAINE42008
Otisfield GrMAINE31975
Seboomook LkMAINE32006
GreenvilleMAINE32022
BenedictaMAINE32022
Grnd Lk StrmMAINE31993
Baker LakeMAINE32009
Heron LakeMAINE32003
FreedomMAINE22006
EastbrookMAINE21981
AuroraMAINE21994
Carrying PlMAINE22005
WinnMAINE21998
LudlowMAINE21998
Horse MtnMAINE21994
TelosMAINE21995
RomeMAINE22001
Clayton Lake 2MAINE22013
CornvilleMAINE22019
MilanNEW-HAMPSHIRE21997
ClarksvilleNEW-HAMPSHIRE22023
Horseshoe L.NEW-YORK22013

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