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Species · North Carolina · BBS 2025 Release · 1966–2024

Worm-eating Warbler Population Trend in North Carolina

All statesForest birds

Worm-eating Warbler in North Carolina has surged: up 129% on the route-weighted index since 1971.

+129%Since 1971TrendPercent 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 →
59Routes 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 →
55YearsYears 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 North CarolinaNotable 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 North Carolina: up 129% on the route-weighted index since 1971.

Worm-eating Warbler Population Forecast in North Carolina

If the recent trend holds, Worm-eating Warbler in North Carolina is projected to rise about 89% by 2029 — from 0.51 in 2024 to a central estimate of 0.97 (95% range 0.21–1.7). A 5-year backtest shows a typical error of ±108.3%, with 100% of held-out values landing inside the 95% band.

+89%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 →
0.97Projected 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 →
0.21–1.795% 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 →
±108.3%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, Worm-eating Warbler in North Carolina is projected to rise about 89% by 2029 — from 0.51 in 2024 to a central estimate of 0.97 (95% range 0.21–1.7). A 5-year backtest shows a typical error of ±108.3%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20250.950.191.7
20260.950.191.7
20270.960.201.7
20280.970.211.7
20290.970.211.7

Worm-eating Warbler Survey Routes in North Carolina

Routes recording Worm-eating Warbler in North Carolina.
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 →
Fontana1320241968
Mashoes819821971
Table Rock620221994
Waterville520241994
Merrimon420191975
Andrews419981994
Brevard320221968
Cullowhee320231974
Newport320221995
Highlands320241994
Oteen320241976
Kinston220081997
California220131972
Kyle220211994
French Broad River220232009
Todd220102003
Milltail Cr220241992
Spring Hope220242002
Eden220182018
Shallotte119891989
Myrtle Grove120051995
Hallsboro120162011
Sheep Ridge120161994
Arapahoe119941994
Beargrass119811981

Worm-eating Warbler Population Trend in Other States

alabamaarkansasconnecticutdelawaregeorgiaillinoisindianaiowakentuckylouisianamarylandmassachusettsmississippimissourinew-hampshirenew-jerseynew-yorkohiooklahomapennsylvaniarhode-islandsouth-carolinatennesseetexasvirginiawest-virginiawisconsin

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