BirdAnalyst
Species · BCR 13 · BBS 2025 Release · 1966–2024

Cliff Swallow In Lower Great Lakes / St. Lawrence Plain

All regionsLower Great Lakes / St. Lawrence PlainAerial insectivores

Cliff Swallow in Lower Great Lakes / St. Lawrence Plain has surged: up 157% on the route-weighted index since 1968.

+157%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 →
62Routes 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 increasecomputed 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 surged in Lower Great Lakes / St. Lawrence Plain: up 157% on the route-weighted index since 1968.

Cliff Swallow In Lower Great Lakes / St. Lawrence Plain Population Forecast

If the recent trend holds, Cliff Swallow in Lower Great Lakes / St. Lawrence Plain is projected to fall about 16% by 2029 — from 1.4 in 2024 to a central estimate of 1.2 (95% range 0.39–2.0). A 5-year backtest shows a typical error of ±40.2%, with 80% of held-out values landing inside the 95% band.

-16%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 →
1.2Projected 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 →
0.39–2.095% 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 →
±40.2%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, Cliff Swallow in Lower Great Lakes / St. Lawrence Plain is projected to fall about 16% by 2029 — from 1.4 in 2024 to a central estimate of 1.2 (95% range 0.39–2.0). A 5-year backtest shows a typical error of ±40.2%, with 80% 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 →
20251.20.382.0
20261.20.382.0
20271.20.392.0
20281.20.392.0
20291.20.392.0

Routes In Lower Great Lakes / St. Lawrence Plain

Routes recording Cliff Swallow 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 →
Herner CrnsOHIO512024
West BangorNEW-YORK371998
HarrisvillePENNSYLVANIA182011
WaddingtonNEW-YORK121998
LucerneOHIO112024
WillsboroNEW-YORK102002
North EastonNEW-YORK82017
NashvilleNEW-YORK72018
ByronNEW-YORK72007
NaplesNEW-YORK62023
Grand IsleVERMONT61985
Cherry HillNEW-YORK51998
OneidaNEW-YORK52010
W ShokanNEW-YORK42003
BranchportNEW-YORK42023
OgdensburgNEW-YORK42016
HighlandNEW-YORK31997
E YoungstownNEW-YORK32019
Alder CreekNEW-YORK31998
SalemNEW-YORK31976
ParishvilleNEW-YORK31980
PhiladelphiaNEW-YORK32022
MaysvilleOHIO32010
EspyvillePENNSYLVANIA32024
RhinebeckNEW-YORK22016

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