BirdAnalyst
Species · North Carolina · BBS 2026 Release · 1966–2025

Black-throated Blue Warbler Population Trend in North Carolina

All statesForest birds

Black-throated Blue Warbler in North Carolina has surged: up 12× on the route-weighted index since 1970.

12×Since 1970TrendPercent 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 →
22Routes 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 Black-throated Blue 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 →

Black-throated Blue Warbler has surged in North Carolina: up 12× on the route-weighted index since 1970.

Black-throated Blue Warbler Population Forecast in North Carolina

If the recent trend holds, Black-throated Blue Warbler in North Carolina is projected to rise about 61% by 2030 — from 0.89 in 2025 to a central estimate of 1.4 (95% range 0.43–2.4). A 5-year backtest shows a typical error of ±37.5%, with 100% of held-out values landing inside the 95% band.

+61%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 →
1.4Projected 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 →
0.43–2.495% 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 →
±37.5%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, Black-throated Blue Warbler in North Carolina is projected to rise about 61% by 2030 — from 0.89 in 2025 to a central estimate of 1.4 (95% range 0.43–2.4). A 5-year backtest shows a typical error of ±37.5%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20261.40.382.4
20271.40.392.4
20281.40.412.4
20291.40.422.4
20301.40.432.4

Black-throated Blue Warbler Survey Routes in North Carolina

Routes recording Black-throated Blue 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 →
Kyle3420241994
N. Mills Riv2519951994
Linville1820251976
French Broad River1520252001
Andrews1019981994
Cherokee1020252011
Cullowhee620251974
Waterville520251994
Busick520021994
Oakboro419771977
Marshall220231999
Todd220241995
Oteen220241980
Table Rock120221994
Highlands120241994
Jonas Ridge119711971
Brevard120131987
Fontana120171968
Call119921970
Pinelog120112002
Hendersonvil119971996
Murphy120142006

Black-throated Blue Warbler Population Trend in Other States

connecticutgeorgiamainemarylandmassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorkpennsylvaniarhode-islandtennesseevermontvirginiawest-virginiawisconsin

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