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

Worm-eating Warbler Population Trend in Louisiana

All statesForest birds

Worm-eating Warbler in Louisiana has surged: up 315% on the route-weighted index since 1969.

+315%Since 1969TrendPercent 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 →
30Routes 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 →
50YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Worm-eating Warbler Trends in LouisianaNotable 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 →

Worm-eating Warbler has surged in Louisiana: up 315% on the route-weighted index since 1969.

Worm-eating Warbler Population Forecast in Louisiana

If the recent trend holds, Worm-eating Warbler in Louisiana is projected to fall about 46% by 2030 — from 0.36 in 2025 to a central estimate of 0.20 (95% range 0.00–0.42). A 5-year backtest shows a typical error of ±60.5%, with 20% of held-out values landing inside the 95% band.

-46%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 →
0.20Projected 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 →
0.00–0.4295% 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 →
±60.5%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, Worm-eating Warbler in Louisiana is projected to fall about 46% by 2030 — from 0.36 in 2025 to a central estimate of 0.20 (95% range 0.00–0.42). A 5-year backtest shows a typical error of ±60.5%, with 20% of held-out values landing inside the 95% band.19672030
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 →
20260.190.000.42
20270.190.000.42
20280.190.000.42
20290.190.000.42
20300.200.000.42

Worm-eating Warbler Survey Routes in Louisiana

Routes recording Worm-eating Warbler in Louisiana.
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 →
Enterprise520252008
Chatham419711967
Hargis320102005
Fort Jessup220211999
Ivan220132006
Easton219811980
Trout220251994
Goodwill220242021
Norwood220252009
Haughton119911991
Linville120251998
Plettenberg120221973
Hargis 2120142013
Clay120101968
Franklinton120162016
Greensburg120222022
Many119911991
Marion119961988
Grayson120182009
Evelyn120242012
Flat Creek120251998
Zwolle120231998
Mount Union120252021
Womack120252022
Pine Prairie119961996

Worm-eating Warbler Population Trend in Other States

alabamaarkansasconnecticutdelawaregeorgiaillinoisindianaiowakentuckymarylandmassachusettsmississippimissourinew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniarhode-islandsouth-carolinatennesseetexasvirginiawest-virginiawisconsin

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