BirdAnalyst
Species · Connecticut · BBS 2025 Release · 1966–2024

Brown Thrasher Population Trend in Connecticut

All statesGeneralists

Brown Thrasher in Connecticut has collapsed: down 97% on the route-weighted index since 1968.

-97%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 →
19Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
51YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Brown Thrasher Trends in ConnecticutNotable 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 Connecticut: down 97% on the route-weighted index since 1968.

Brown Thrasher Population Forecast in Connecticut

If the recent trend holds, Brown Thrasher in Connecticut is projected to fall about 100% by 2029 — from 0.11 in 2024 to a central estimate of 0.00 (95% range 0.00–2.6). A 5-year backtest shows a typical error of ±1446%, with 100% 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 →
0.00–2.695% 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 →
±1446%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 Connecticut is projected to fall about 100% by 2029 — from 0.11 in 2024 to a central estimate of 0.00 (95% range 0.00–2.6). A 5-year backtest shows a typical error of ±1446%, with 100% 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 →
20250.000.002.6
20260.000.002.6
20270.000.002.6
20280.000.002.6
20290.000.002.6

Brown Thrasher Survey Routes in Connecticut

Routes recording Brown Thrasher in Connecticut.
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 →
Westbrook219941969
Mystic120231973
E Hartland119911967
Buckingham120011966
Uncasville120171973
Woodstock120051968
Willimantic120071967
No Woodbury120221967
Sherman120141973
Greenwich119961967
Danbury120121968
Warren120101972
Long Hill119901972
Mid Haddam120061973
Southington119961973
New Hartford119871972
Woodstock 2120192017
Warren 2120242024
Granby120171988

Brown Thrasher Population Trend in Other States

alabamaarkansascoloradodelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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