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Species · BCR 14 · BBS 2026 Release · 1966–2025

Chimney Swift In Atlantic Northern Forest

All regionsAtlantic Northern ForestAerial insectivores

Chimney Swift in Atlantic Northern Forest has fallen sharply: down 59% on the route-weighted index since 1968.

-59%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 →
150Routes 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 →
59YearsYears 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 →

Chimney Swift has fallen sharply in Atlantic Northern Forest: down 59% on the route-weighted index since 1968.

Chimney Swift In Atlantic Northern Forest Population Forecast

If the recent trend holds, Chimney Swift in Atlantic Northern Forest is projected to fall about 70% by 2030 — from 2.6 in 2025 to a central estimate of 0.76 (95% range 0.00–2.2). A 5-year backtest shows a typical error of ±57.8%, with 40% of held-out values landing inside the 95% band.

-70%Change by 2030TrendPercent 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 →
0.76Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–2.295% 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 →
±57.8%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, Chimney Swift in Atlantic Northern Forest is projected to fall about 70% by 2030 — from 2.6 in 2025 to a central estimate of 0.76 (95% range 0.00–2.2). A 5-year backtest shows a typical error of ±57.8%, with 40% of held-out values landing inside the 95% band.19662030
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 →
20261.10.002.5
20270.980.002.4
20280.910.002.4
20290.840.002.3
20300.760.002.2

Routes In Atlantic Northern Forest

Routes recording Chimney Swift 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 →
N OrangeMASSACHUSETTS172025
ConcordNEW-HAMPSHIRE172025
WatervilleVERMONT171980
New HartfordCONNECTICUT141987
Otisfield GrMAINE132015
NorthfieldMAINE131979
CanterburyNEW-HAMPSHIRE122025
GaysvilleVERMONT112025
HarmonyMAINE102025
WaiteMAINE101977
AuroraMAINE92013
CharlestonMAINE92019
W RutlandVERMONT92025
WestbrookMAINE82024
HermonMAINE82021
Pillsbury PdMAINE81968
HancockMASSACHUSETTS82014
LempsterNEW-HAMPSHIRE82024
CarrabassettMAINE72023
Gilmantn I WNEW-HAMPSHIRE72025
Number FourNEW-YORK71987
StoweVERMONT72024
HudsonMAINE62016
ChesterfieldMASSACHUSETTS62025
PeterboroughNEW-HAMPSHIRE62025

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.