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

Tree Swallow In Lower Great Lakes / St. Lawrence Plain

All regionsLower Great Lakes / St. Lawrence PlainAerial insectivores

Tree Swallow in Lower Great Lakes / St. Lawrence Plain has edged down: down 15% on the route-weighted index since 1968.

-15%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 →
86Routes 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 Tree Swallow in Lower Great Lakes / St. Lawrence Plain. See the full index history below.

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

If the recent trend holds, Tree Swallow in Lower Great Lakes / St. Lawrence Plain is projected to rise about 120% by 2030 — from 3.0 in 2025 to a central estimate of 6.7 (95% range 2.7–11). A 5-year backtest shows a typical error of ±111.4%, with 40% of held-out values landing inside the 95% band.

+120%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 →
6.7Projected 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 →
2.7–1195% 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 →
±111.4%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, Tree Swallow in Lower Great Lakes / St. Lawrence Plain is projected to rise about 120% by 2030 — from 3.0 in 2025 to a central estimate of 6.7 (95% range 2.7–11). A 5-year backtest shows a typical error of ±111.4%, 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 →
20266.72.611
20276.72.611
20286.72.711
20296.72.711
20306.72.711

Routes In Lower Great Lakes / St. Lawrence Plain

Routes recording Tree 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 →
Ballston LkNEW-YORK341995
HinesburgVERMONT341994
GarrettsvileOHIO241991
ArgyleNEW-YORK222024
RomulusNEW-YORK212000
West BangorNEW-YORK211999
Alder CreekNEW-YORK182004
BristolVERMONT172025
MacdougallNEW-YORK162025
WatertownNEW-YORK122012
BranchportNEW-YORK112024
NashvilleNEW-YORK102018
North PownalVERMONT102025
PulaskiNEW-YORK92025
N WilmurtNEW-YORK91998
AkeleyPENNSYLVANIA91979
OneidaNEW-YORK82010
HiramOHIO82025
ParishvilleNEW-YORK72022
HebronOHIO72025
AusterlitzNEW-YORK62025
SheridanNEW-YORK61998
WaddingtonNEW-YORK61998
CayugaNEW-YORK52025
E YoungstownNEW-YORK52025

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