BirdAnalyst
Species · BCR 13 · BBS 2026 Release · 1966–2025

Chimney Swift In Lower Great Lakes / St. Lawrence Plain

All regionsLower Great Lakes / St. Lawrence PlainAerial insectivores

Chimney Swift in Lower Great Lakes / St. Lawrence Plain has declined: down 40% on the route-weighted index since 1968.

-40%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 →
83Routes 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 →

No notable trend signals for Chimney Swift in Lower Great Lakes / St. Lawrence Plain. See the full index history below.

Chimney Swift In Lower Great Lakes / St. Lawrence Plain Population Forecast

If the recent trend holds, Chimney Swift in Lower Great Lakes / St. Lawrence Plain is projected to rise about 29% by 2030 — from 4.5 in 2025 to a central estimate of 5.8 (95% range 3.0–8.6). A 5-year backtest shows a typical error of ±36.8%, with 100% of held-out values landing inside the 95% band.

+29%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 →
5.8Projected 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 →
3.0–8.695% 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 →
±36.8%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 Lower Great Lakes / St. Lawrence Plain is projected to rise about 29% by 2030 — from 4.5 in 2025 to a central estimate of 5.8 (95% range 3.0–8.6). A 5-year backtest shows a typical error of ±36.8%, with 100% 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 →
20265.93.18.7
20275.93.18.7
20285.93.18.7
20295.93.18.6
20305.83.08.6

Routes In Lower Great Lakes / St. Lawrence Plain

Routes recording Chimney Swift in Lower Great Lakes / St. Lawrence Plain.
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 →
Slippery RkPENNSYLVANIA371994
HarmonsburgPENNSYLVANIA322025
MacdougallNEW-YORK252025
GarrettsvileOHIO251991
BranchportNEW-YORK212024
CloverPENNSYLVANIA192025
LattasburgOHIO172025
PeruOHIO161978
HiramOHIO122025
Valley CityOHIO122025
Herner CrnsOHIO112025
HamburgNEW-YORK102025
New SomersetOHIO101993
HighlandNEW-YORK92022
North EastonNEW-YORK92025
MaysvilleOHIO92012
MiddlefieldOHIO82017
Ballston LkNEW-YORK71995
LenoxOHIO72025
EspyvillePENNSYLVANIA72025
TeeplevillePENNSYLVANIA72025
PenfieldNEW-YORK62025
Alder CreekNEW-YORK62004
AkeleyPENNSYLVANIA61979
TrumansburgNEW-YORK52023

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