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

Magnolia Warbler Population Trend in New Hampshire

All statesForest birds

Magnolia Warbler in New Hampshire has declined: down 38% on the route-weighted index since 1968.

-38%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 Magnolia 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 Magnolia Warbler in New Hampshire. See the full index history below.

Magnolia Warbler Population Forecast in New Hampshire

If the recent trend holds, Magnolia Warbler in New Hampshire is projected to rise about 31% by 2030 — from 1.6 in 2025 to a central estimate of 2.1 (95% range 0.89–3.3). A 5-year backtest shows a typical error of ±82.8%, with 60% of held-out values landing inside the 95% band.

+31%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 →
2.1Projected 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 →
0.89–3.395% 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 →
±82.8%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, Magnolia Warbler in New Hampshire is projected to rise about 31% by 2030 — from 1.6 in 2025 to a central estimate of 2.1 (95% range 0.89–3.3). A 5-year backtest shows a typical error of ±82.8%, with 60% 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 →
20262.10.893.3
20272.10.893.3
20282.10.893.3
20292.10.893.3
20302.10.893.3

Magnolia Warbler Survey Routes in New Hampshire

Routes recording Magnolia 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 →
Dixville Notch 21120252018
Dixvil Notch1020171966
Stratford620251966
Franconia420251966
Milan420251966
Clarksville420251966
Hopkinton219951967
Crawford Not219751966
Jefferson Hl220251966
Glen220251975
Peterborough120161982
Brentwood119771977
Fitzwilliam119981974
Dover119821968
Epsom119921969
Concord120061973
Strafford120181968
Canterbury120021966
Gilmantn I W119841970
Wilmot120251974
Mt Chocorua120251966
Walpole120231970
Marlow120111967
Lempster120251972
Jeffers Ntch120251993

Magnolia Warbler Population Trend in Other States

connecticutmainemarylandmassachusettsmichiganminnesotanew-jerseynew-yorknorth-carolinaohiopennsylvaniavermontvirginiawest-virginiawisconsin

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