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

Brown Thrasher Population Trend in Tennessee

All statesGeneralists

Brown Thrasher in Tennessee has edged down: down 17% on the route-weighted index since 1968.

-17%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 →
53Routes 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 →
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 Brown Thrasher Trends in TennesseeNotable 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 Brown Thrasher in Tennessee. See the full index history below.

Brown Thrasher Population Forecast in Tennessee

If the recent trend holds, Brown Thrasher in Tennessee is projected to fall about 32% by 2029 — from 5.5 in 2024 to a central estimate of 3.8 (95% range 2.6–5.0). A 5-year backtest shows a typical error of ±18.7%, with 60% of held-out values landing inside the 95% band.

-32%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 →
3.8Projected 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 →
2.6–5.095% 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 →
±18.7%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 Tennessee is projected to fall about 32% by 2029 — from 5.5 in 2024 to a central estimate of 3.8 (95% range 2.6–5.0). A 5-year backtest shows a typical error of ±18.7%, 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 →
20253.92.75.1
20263.82.65.0
20273.82.65.0
20283.82.65.0
20293.82.65.0

Brown Thrasher Survey Routes in Tennessee

Routes recording Brown Thrasher in Tennessee.
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 →
Big Sandy1720241966
Humboldt1320241966
Collinwood1320241966
Mansfield1120241966
Union Hill1020241967
Glen1020241966
Lovell1020191966
Signal Mtn920241979
Oliver Spgs820221966
Corryton Rd820191966
Brownsville620241966
Silerton620241966
Allens Brdge620231966
Whiteville520241966
Petersburg520131966
Red Bank519781967
Climer520041967
Indian Mound 2520232004
Tibbs420241966
Sweetlips420231966
Peytonsville420241966
Bradyville420191966
Tullahoma420151967
Silver Pt420241966
Smokey Jct420221966

Brown Thrasher Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatexasvermontvirginiawest-virginiawisconsinwyoming

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