BirdAnalyst
Species · BCR 30 · BBS 2025 Release · 1966–2024

Brown Thrasher In New England / Mid-Atlantic Coast

All regionsNew England / Mid-Atlantic CoastGeneralists

Brown Thrasher in New England / Mid-Atlantic Coast has fallen sharply: down 61% on the route-weighted index since 1968.

-61%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 →
159Routes 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 →

Brown Thrasher has fallen sharply in New England / Mid-Atlantic Coast: down 61% on the route-weighted index since 1968.

Forecast

If the recent trend holds, Brown Thrasher in New England / Mid-Atlantic Coast is projected to fall about 61% by 2029 — from 2.1 in 2024 to a central estimate of 0.80 (95% range 0.00–2.2). A 5-year backtest shows a typical error of ±47.1%, with 80% of held-out values landing inside the 95% band.

-61%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 →
0.80Projected 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 →
0.00–2.295% 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 →
±47.1%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, Brown Thrasher in New England / Mid-Atlantic Coast is projected to fall about 61% by 2029 — from 2.1 in 2024 to a central estimate of 0.80 (95% range 0.00–2.2). A 5-year backtest shows a typical error of ±47.1%, 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 →
20251.00.002.4
20260.950.002.4
20270.900.002.3
20280.850.002.3
20290.800.002.2

Routes In New England / Mid-Atlantic Coast

Routes recording Brown Thrasher in New England / Mid-Atlantic Coast.
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 →
PomfretMARYLAND152024
HughesvilleMARYLAND142024
Spraguetown 2NEW-JERSEY122007
TruhartVIRGINIA122024
Tall TimbersMARYLAND92014
Grove NeckMARYLAND91996
Milton 2DELAWARE82017
BlackbirdDELAWARE72024
Pepperbox 2DELAWARE72024
La PlataMARYLAND72009
Forest GroveMARYLAND72023
Island CreekMARYLAND72024
DeepwaterNEW-JERSEY71977
MelitotaMARYLAND52024
MatthewsMARYLAND52024
MadisonMARYLAND52024
St. George'S IslandMARYLAND52017
DavidsnvilleMARYLAND52024
WalnutMARYLAND52024
Mt MiseryNEW-JERSEY51989
Pedricktown 2NEW-JERSEY52024
HauppaugeNEW-YORK52008
QuinbyVIRGINIA52024
BrandonVIRGINIA52024
Holleyville 2DELAWARE42024

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