BirdAnalyst
Species · New Hampshire · BBS 2025 Release · 1966–2024

Blue-winged Warbler Population Trend in New Hampshire

All statesForest birds

Blue-winged Warbler in New Hampshire has declined: down 29% on the route-weighted index since 1971.

-29%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 →
10Routes 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 →
35YearsYears 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-winged Warbler Trends in New HampshireNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Blue-winged Warbler in New Hampshire. See the full index history below.

Blue-winged Warbler Population Forecast in New Hampshire

If the recent trend holds, Blue-winged Warbler in New Hampshire is projected to stay roughly flat through 2029, near 0.10 (95% range 0.00–0.25). A 5-year backtest shows a typical error of ±235.6%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.10Projected 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 →
0.00–0.2595% 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 →
±235.6%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-winged Warbler in New Hampshire is projected to stay roughly flat through 2029, near 0.10 (95% range 0.00–0.25). A 5-year backtest shows a typical error of ±235.6%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20250.100.000.25
20260.100.000.25
20270.100.000.25
20280.100.000.25
20290.100.000.25

Blue-winged Warbler Survey Routes in New Hampshire

Routes recording Blue-winged Warbler in New Hampshire.
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 →
Hopkinton219961996
Brentwood119981971
Fitzwilliam119821982
Dover120241967
Epsom119991986
Concord119981998
Strafford120001988
East Kingston120171999
Mt Chocorua119751975
Franconia119681968

Blue-winged Warbler Population Trend in Other States

alabamaarkansasconnecticutdelawaregeorgiaillinoisindianaiowakentuckymarylandmassachusettsmichiganminnesotamississippimissourinew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniarhode-islandtennesseevermontvirginiawest-virginiawisconsin

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