BirdAnalyst
Species · BCR 14 · BBS 2025 Release · 1966–2024

Brown Thrasher In Atlantic Northern Forest

All regionsAtlantic Northern ForestGeneralists

Brown Thrasher in Atlantic Northern Forest has collapsed: down 85% on the route-weighted index since 1968.

-85%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 →
120Routes 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 collapsed in Atlantic Northern Forest: down 85% on the route-weighted index since 1968.

Forecast

If the recent trend holds, Brown Thrasher in Atlantic Northern Forest is projected to fall about 100% by 2029 — from 0.08 in 2024 to a central estimate of 0.00 (95% range 0.00–0.83). A 5-year backtest shows a typical error of ±397.7%, with 60% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–0.8395% 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 →
±397.7%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 Atlantic Northern Forest is projected to fall about 100% by 2029 — from 0.08 in 2024 to a central estimate of 0.00 (95% range 0.00–0.83). A 5-year backtest shows a typical error of ±397.7%, with 60% 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 →
20250.000.000.83
20260.000.000.83
20270.000.000.83
20280.000.000.83
20290.000.000.83

Routes In Atlantic Northern Forest

Routes recording Brown Thrasher in Atlantic Northern Forest.
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 →
BentonMAINE51980
KasoagNEW-YORK52007
Dexter LakeNEW-YORK51975
Forest StaMAINE41976
Church HillMAINE42017
ManchesterMAINE31983
Jefferson HlNEW-HAMPSHIRE32022
East HavenVERMONT32023
WatervilleVERMONT31980
WestbrookMAINE22015
BiddefordMAINE22009
HancockMAINE22012
CastineMAINE21977
MedwayMAINE22016
CornvilleMAINE22023
CheshireMASSACHUSETTS21993
MckeeverNEW-YORK21993
SpeculatorNEW-YORK22017
WanakenaNEW-YORK22018
GabrielsNEW-YORK21983
SciotaNEW-YORK21989
HardwickVERMONT22011
New HartfordCONNECTICUT11987
NewcastleMAINE11980
BethelMAINE12010

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