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

Magnolia Warbler Population Trend in New Hampshire

All statesForest birds

Magnolia Warbler in New Hampshire has declined: down 44% on the route-weighted index since 1968.

-44%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 →
58YearsYears 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 49% by 2029 — from 1.5 in 2024 to a central estimate of 2.2 (95% range 0.94–3.4). A 5-year backtest shows a typical error of ±85.7%, with 60% of held-out values landing inside the 95% band.

+49%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 →
2.2Projected 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 →
0.94–3.495% 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 →
±85.7%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 49% by 2029 — from 1.5 in 2024 to a central estimate of 2.2 (95% range 0.94–3.4). A 5-year backtest shows a typical error of ±85.7%, with 60% of held-out values landing inside the 95% band.19662029
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 →
20252.20.943.4
20262.20.943.4
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20292.20.943.4

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 →
Dixvil Notch1020171966
Clarksville720241966
Franconia620241966
Dixville Notch 2620242018
Wilmot520211974
Stratford520241966
Hopkinton219951967
Mt Chocorua220241966
Lempster220241972
Crawford Not219751966
Jefferson Hl220231966
Jeffers Ntch220241993
Peterborough120161982
Brentwood119771977
Fitzwilliam119981974
Dover119821968
Epsom119921969
Concord120061973
Strafford120181968
Canterbury120021966
Gilmantn I W119841970
Walpole120231970
Marlow120111967
Milan120241966
Glen120241975

Magnolia Warbler Population Trend in Other States

connecticutmainemarylandmassachusettsmichiganminnesotanew-jerseynew-yorknorth-carolinaohiopennsylvaniavermontvirginiawest-virginiawisconsin

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