BirdAnalyst
Species · Tennessee · BBS 2026 Release · 1966–2025

Brown-headed Cowbird Population Trend in Tennessee

All statesGeneralists

Brown-headed Cowbird in Tennessee has increased: up 26% on the route-weighted index since 1968.

+26%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 →
54Routes 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 →
59YearsYears 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-headed Cowbird 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-headed Cowbird in Tennessee. See the full index history below.

Brown-headed Cowbird Population Forecast in Tennessee

If the recent trend holds, Brown-headed Cowbird in Tennessee is projected to stay roughly flat through 2030, near 11 (95% range 7.2–14). A 5-year backtest shows a typical error of ±8.5%, with 100% of held-out values landing inside the 95% band.

-9%Change by 2030TrendPercent 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 →
11Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
7.2–1495% 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 →
±8.5%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-headed Cowbird in Tennessee is projected to stay roughly flat through 2030, near 11 (95% range 7.2–14). A 5-year backtest shows a typical error of ±8.5%, with 100% of held-out values landing inside the 95% band.19662030
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 →
2026117.214
2027117.214
2028117.214
2029117.214
2030117.214

Brown-headed Cowbird Survey Routes in Tennessee

Routes recording Brown-headed Cowbird 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 →
Mansfield5320251966
Lovell3720191966
Humboldt3420251966
Bradyville3420211966
Corryton Rd3320191966
Big Sandy3020251966
Belotes Bend2320181966
Indian Mound2119981966
Collinwood2020251966
Indian Mound 21720232004
Brownsville1620251966
Whiteville1520251966
Trenton1520231966
Pond Creek1420251966
Silver Pt1420241966
Trace Collinwood1220182015
Peytonsville1120251966
Union Hill920241967
Harbuck920231997
Glen820251966
Trace Lewis820172013
Smokey Jct720221966
Jefferson Cty720111966
Tiptonville620251966
Silerton620241967

Brown-headed Cowbird Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.