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

Purple Martin In Atlantic Northern Forest

All regionsAtlantic Northern ForestAerial insectivores

Purple Martin in Atlantic Northern Forest 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 →
38Routes 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 →
35YearsYears 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 →

Purple Martin has collapsed in Atlantic Northern Forest: down 79% on the route-weighted index since 1968.

Purple Martin In Atlantic Northern Forest Population Forecast

If the recent trend holds, Purple Martin in Atlantic Northern Forest is projected to stay roughly flat through 2015, near 0.07 (95% range 0.00–0.35). A 5-year backtest shows a typical error of ±481.2%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2015TrendPercent 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 →
0.07Projected 2015 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.3595% 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 →
±481.2%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, Purple Martin in Atlantic Northern Forest is projected to stay roughly flat through 2015, near 0.07 (95% range 0.00–0.35). A 5-year backtest shows a typical error of ±481.2%, with 100% of held-out values landing inside the 95% band.19662015
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 →
20110.090.000.37
20120.080.000.37
20130.080.000.36
20140.070.000.36
20150.070.000.35

Routes In Atlantic Northern Forest

Routes recording Purple Martin 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 →
WinnMAINE121979
CambridgeMAINE101973
Grnd Lk StrmMAINE92000
HopkintonNEW-HAMPSHIRE71985
Gilmantn I WNEW-HAMPSHIRE61990
HighmarketNEW-YORK61985
BiddefordMAINE51976
Otisfield GrMAINE51989
WashburnMAINE41991
Crawford NotNEW-HAMPSHIRE41972
Hope FallsNEW-YORK31977
GreensboroVERMONT31968
NewcastleMAINE21972
HarmonyMAINE22010
BrooksMAINE21996
CharlestonMAINE21977
WytopitlockMAINE21982
MedwayMAINE21979
HudsonMAINE21999
LempsterNEW-HAMPSHIRE22000
East CalaisVERMONT21976
BethelMAINE11991
HartfordMAINE11981
ManchesterMAINE11989
East TroyMAINE11972

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