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Species · Maryland · BBS 2026 Release · 1966–2025

Pine Warbler Population Trend in Maryland

All statesForest birds

Pine Warbler in Maryland has surged: up 277% on the route-weighted index since 1968.

+277%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 →
52Routes 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 Pine Warbler Trends in MarylandNotable 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 →

Pine Warbler has surged in Maryland: up 277% on the route-weighted index since 1968.

Pine Warbler Population Forecast in Maryland

If the recent trend holds, Pine Warbler in Maryland is projected to fall about 14% by 2030 — from 6.5 in 2025 to a central estimate of 5.6 (95% range 3.5–7.7). A 5-year backtest shows a typical error of ±26%, with 100% of held-out values landing inside the 95% band.

-14%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 →
5.6Projected 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 →
3.5–7.795% 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 →
±26%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, Pine Warbler in Maryland is projected to fall about 14% by 2030 — from 6.5 in 2025 to a central estimate of 5.6 (95% range 3.5–7.7). A 5-year backtest shows a typical error of ±26%, 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 →
20265.43.37.5
20275.43.47.5
20285.53.47.6
20295.53.57.6
20305.63.57.7

Pine Warbler Survey Routes in Maryland

Routes recording Pine Warbler in Maryland.
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 →
Furnace Town4820252015
Madison4720251966
Honga4120251966
Cokesbury3920251966
Forest Grove1920232011
Berlin1420251980
Walnut1120241999
Sinepuxent1019781966
St. George'S Island1020172015
Snow Hill919761966
Indiantown920141977
Oldtown820251970
Piney Grove820251995
Island Creek820251991
Tall Timbers720141966
Newark720251966
Fruitland619981966
Hughesville520251966
Pomfret520241966
La Plata420091967
Green Ridge420251995
Millington320241967
Nottingham320232005
Pr Frederick320251991
Jones219941977

Pine Warbler Population Trend in Other States

alabamaarkansasconnecticutdelawarefloridageorgiaillinoisindianakentuckylouisianamainemassachusettsmichiganminnesotamississippimissourinew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniarhode-islandsouth-carolinatennesseetexasvermontvirginiawest-virginiawisconsin

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