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

Chimney Swift In Atlantic Northern Forest

All regionsAtlantic Northern ForestAerial insectivores

Chimney Swift in Atlantic Northern Forest has fallen sharply: down 60% on the route-weighted index since 1968.

-60%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 →
58YearsYears 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 60% 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 2029 — from 2.4 in 2024 to a central estimate of 0.72 (95% range 0.00–2.1). A 5-year backtest shows a typical error of ±49.8%, with 60% of held-out values landing inside the 95% band.

-70%Change 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 →
0.72Projected 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 →
0.00–2.195% 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 →
±49.8%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 2029 — from 2.4 in 2024 to a central estimate of 0.72 (95% range 0.00–2.1). A 5-year backtest shows a typical error of ±49.8%, with 60% of held-out values landing inside the 95% band.19662029
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 →
20251.00.002.4
20260.950.002.4
20270.880.002.3
20280.800.002.2
20290.720.002.1

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 →
ConcordNEW-HAMPSHIRE182024
WatervilleVERMONT171980
New HartfordCONNECTICUT141987
Otisfield GrMAINE132015
NorthfieldMAINE131979
N OrangeMASSACHUSETTS132024
WaiteMAINE101977
MontereyMASSACHUSETTS102024
AuroraMAINE92013
CharlestonMAINE92019
CanterburyNEW-HAMPSHIRE92024
Gilmantn I WNEW-HAMPSHIRE92024
WestbrookMAINE82024
Pillsbury PdMAINE81968
HancockMASSACHUSETTS82014
FitzwilliamNEW-HAMPSHIRE82022
LempsterNEW-HAMPSHIRE82024
WanakenaNEW-YORK82024
CarrabassettMAINE72023
Number FourNEW-YORK71987
StoweVERMONT72024
HermonMAINE62018
HudsonMAINE62016
SearsportMAINE62024
Dexter LakeNEW-YORK61975

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