BirdAnalyst
Species · New Hampshire · BBS 2026 Release · 1966–2025

Yellow Warbler Population Trend in New Hampshire

All statesForest birds

Yellow Warbler in New Hampshire has edged up: up 14% on the route-weighted index since 1968.

+14%Since 1968TrendPercent 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 →
25Routes 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 →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Yellow 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 Yellow Warbler in New Hampshire. See the full index history below.

Yellow Warbler Population Forecast in New Hampshire

If the recent trend holds, Yellow Warbler in New Hampshire is projected to fall about 21% by 2030 — from 4.7 in 2025 to a central estimate of 3.7 (95% range 1.5–5.9). A 5-year backtest shows a typical error of ±8%, with 100% of held-out values landing inside the 95% band.

-21%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 →
3.7Projected 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 →
1.5–5.995% 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 →
±8%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, Yellow Warbler in New Hampshire is projected to fall about 21% by 2030 — from 4.7 in 2025 to a central estimate of 3.7 (95% range 1.5–5.9). A 5-year backtest shows a typical error of ±8%, with 100% of held-out values landing inside the 95% band.19662030
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 →
20263.81.66.0
20273.81.56.0
20283.71.56.0
20293.71.55.9
20303.71.55.9

Yellow Warbler Survey Routes in New Hampshire

Routes recording Yellow 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 →
Fitzwilliam1920251966
Stratford1420251966
Canterbury720251966
Marlow720251966
Dover620251966
Milan620251966
East Kingston620251999
Strafford520251966
Brentwood419981966
Concord420251966
Wilmot420251966
Jefferson Hl420251966
Clarksville420251974
Peterborough320251966
Hopkinton320251966
Gilmantn I W320251969
Mt Chocorua320251970
Glen320251976
Walpole220251966
Lempster220251969
Epsom120251966
Franconia120041966
Dixvil Notch120171966
Jeffers Ntch120241993
Dixville Notch 2120252019

Yellow Warbler Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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