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

Cliff Swallow In Atlantic Northern Forest

All regionsAtlantic Northern ForestAerial insectivores

Cliff Swallow in Atlantic Northern Forest has collapsed: down 94% on the route-weighted index since 1968.

-94%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 →
129Routes 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 →

Cliff Swallow has collapsed in Atlantic Northern Forest: down 94% on the route-weighted index since 1968.

Forecast

If the recent trend holds, Cliff Swallow in Atlantic Northern Forest is projected to fall about 100% by 2029 — from 0.31 in 2024 to a central estimate of 0.00 (95% range 0.00–1.8). A 5-year backtest shows a typical error of ±228.1%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–1.895% 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 →
±228.1%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, Cliff Swallow in Atlantic Northern Forest is projected to fall about 100% by 2029 — from 0.31 in 2024 to a central estimate of 0.00 (95% range 0.00–1.8). A 5-year backtest shows a typical error of ±228.1%, with 100% 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 →
20250.000.001.8
20260.000.001.8
20270.000.001.8
20280.000.001.8
20290.000.001.8

Routes In Atlantic Northern Forest

Routes recording Cliff Swallow 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 →
Grnd Lk StrmMAINE931993
BaxterMAINE211988
NorthfieldMAINE201981
Northfld FlsVERMONT191980
Otisfield GrMAINE151993
HermonMAINE121993
Forest StaMAINE121985
GreenwoodMAINE101994
CastineMAINE102000
AuroraMAINE102019
Clayton LakeMAINE101986
CornvilleMAINE102019
Bowdoin CtrMAINE82013
GreenvilleMAINE82022
MedwayMAINE82014
WilmotNEW-HAMPSHIRE81974
StoweVERMONT81992
LudlowMAINE71996
MilanNEW-HAMPSHIRE72024
DannemoraNEW-YORK61978
HardwickVERMONT61994
HartfordMAINE52021
Baker LakeMAINE51994
Cummington 2MASSACHUSETTS52024
GaysvilleVERMONT52017

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