BirdAnalyst
Species · BCR 28 · BBS 2025 Release · 1966–2024

Swainson's Thrush In Appalachian Mountains

All regionsAppalachian MountainsForest birds

Swainson's Thrush in Appalachian Mountains has surged: up 83% on the route-weighted index since 1969.

+83%Since 1969TrendPercent 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 →
33Routes 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 →
52YearsYears 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 →

Swainson's Thrush has surged in Appalachian Mountains: up 83% on the route-weighted index since 1969.

Forecast

If the recent trend holds, Swainson's Thrush in Appalachian Mountains is projected to fall about 22% by 2029 — from 0.08 in 2024 to a central estimate of 0.06 (95% range 0.01–0.12). A 5-year backtest shows a typical error of ±40.6%, with 80% of held-out values landing inside the 95% band.

-22%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 →
0.06Projected 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 →
0.01–0.1295% 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 →
±40.6%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, Swainson's Thrush in Appalachian Mountains is projected to fall about 22% by 2029 — from 0.08 in 2024 to a central estimate of 0.06 (95% range 0.01–0.12). A 5-year backtest shows a typical error of ±40.6%, 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 →
20250.060.000.12
20260.060.010.12
20270.060.010.12
20280.060.010.12
20290.060.010.12

Routes In Appalachian Mountains

Routes recording Swainson's Thrush in Appalachian Mountains.
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 →
Glade Run 2WEST-VIRGINIA142024
Glade RunWEST-VIRGINIA82002
Cherry SprsPENNSYLVANIA62021
Green BankWEST-VIRGINIA41986
WymerWEST-VIRGINIA32015
Platte CoveNEW-YORK22011
Whig HillPENNSYLVANIA21988
VindexMARYLAND11971
LaurensNEW-YORK11978
McdonoughNEW-YORK11997
OxfordNEW-YORK11969
LisleNEW-YORK12009
E NewarkNEW-YORK12014
CattaraugusNEW-YORK11983
DownsvilleNEW-YORK12005
BusickNORTH-CAROLINA11994
LynchPENNSYLVANIA12024
OdinPENNSYLVANIA12015
BetulaPENNSYLVANIA12007
Russell CityPENNSYLVANIA12024
EldredPENNSYLVANIA12015
RasselasPENNSYLVANIA12016
RoulettePENNSYLVANIA12016
LoguePENNSYLVANIA12016
English CtrPENNSYLVANIA11974

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