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

Black-throated Blue Warbler Population Trend in North Carolina

All statesForest birds

Black-throated Blue Warbler in North Carolina has surged: up 13× on the route-weighted index since 1970.

13×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 →
54YearsYears 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 13× 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 stay roughly flat through 2029, near 1.5 (95% range 0.46–2.4). A 5-year backtest shows a typical error of ±27.1%, with 100% of held-out values landing inside the 95% band.

+7%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 →
1.5Projected 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 →
0.46–2.495% 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 →
±27.1%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 stay roughly flat through 2029, near 1.5 (95% range 0.46–2.4). A 5-year backtest shows a typical error of ±27.1%, 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 →
20251.40.402.4
20261.40.412.4
20271.40.432.4
20281.40.442.4
20291.50.462.4

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
Linville1920241976
French Broad River1620242001
Cherokee1320242011
Andrews1019981994
Cullowhee620241974
Busick520021994
Waterville420241994
Oakboro419771977
Marshall220231999
Oteen220241980
Table Rock120221994
Highlands120241994
Jonas Ridge119711971
Brevard120131987
Fontana120171968
Call119921970
Pinelog120112002
Hendersonvil119971996
Murphy120142006
Todd120211995

Black-throated Blue Warbler Population Trend in Other States

connecticutgeorgiamainemarylandmassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorkpennsylvaniarhode-islandtennesseevermontvirginiawest-virginiawisconsin

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