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

Brown-headed Cowbird Population Trend in Tennessee

All statesGeneralists

Brown-headed Cowbird in Tennessee has edged up: up 22% on the route-weighted index since 1968.

+22%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 →
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-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 2029, near 10 (95% range 7.0–14). A 5-year backtest shows a typical error of ±7.3%, with 100% of held-out values landing inside the 95% band.

-8%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 →
10Projected 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 →
7.0–1495% 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 →
±7.3%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 2029, near 10 (95% range 7.0–14). A 5-year backtest shows a typical error of ±7.3%, 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 →
2025107.014
2026107.014
2027107.014
2028107.014
2029107.014

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 →
Mansfield5920241966
Lovell3720191966
Bradyville3420211966
Corryton Rd3320191966
Humboldt2920241966
Big Sandy2620241966
Belotes Bend2320181966
Indian Mound2119981966
Moscow1920241966
Whiteville1820241966
Brownsville1720241966
Indian Mound 21720232004
Tibbs1520241966
Trenton1520231966
Tiptonville1420231966
Silver Pt1420241966
Collinwood1220241966
Trace Collinwood1220182015
Union Hill920241967
Harbuck920231997
Trace Lewis820172013
Peytonsville720241966
Smokey Jct720221966
Jefferson Cty720111966
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 2026-05-22.