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

Blue-gray Gnatcatcher Population Trend in Tennessee

All statesForest birds

Blue-gray Gnatcatcher in Tennessee has surged: up 189% on the route-weighted index since 1968.

+189%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 →
55Routes 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 Blue-gray Gnatcatcher 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 →

long arc increasecomputed 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 →

Blue-gray Gnatcatcher has surged in Tennessee: up 189% on the route-weighted index since 1968.

Blue-gray Gnatcatcher Population Forecast in Tennessee

If the recent trend holds, Blue-gray Gnatcatcher in Tennessee is projected to rise about 60% by 2029 — from 7.5 in 2024 to a central estimate of 12 (95% range 8.6–16). A 5-year backtest shows a typical error of ±68.8%, with 0% of held-out values landing inside the 95% band.

+60%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 →
12Projected 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 →
8.6–1695% 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 →
±68.8%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, Blue-gray Gnatcatcher in Tennessee is projected to rise about 60% by 2029 — from 7.5 in 2024 to a central estimate of 12 (95% range 8.6–16). A 5-year backtest shows a typical error of ±68.8%, with 0% 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 →
2025128.115
2026128.215
2027128.415
2028128.515
2029128.616

Blue-gray Gnatcatcher Survey Routes in Tennessee

Routes recording Blue-gray Gnatcatcher 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 →
Mansfield3920241966
Trace Collinwood2820182016
Big Sandy2420241966
Indian Mound 22420232004
Corryton Rd2320191966
Trace Lewis2320172013
Campbellsville1820171966
Smokey Jct1620221966
Lovell1620191966
Walland1619891966
Sweetlips1520231966
Oliver Spgs1320221966
Jones Gap1320191983
Wrigley1220221966
Lewis Forest1220241966
Silerton1120241975
Humboldt1120241966
Collinwood1120241966
Belotes Bend1020181966
Signal Mtn920241979
Red Bank919781968
Mcfarland919931967
Climer920041969
Mecca920231994
Pond Creek820241966

Blue-gray Gnatcatcher Population Trend in Other States

alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatexasutahvermontvirginiawest-virginiawisconsinwyoming

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