BirdAnalyst
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.

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.