BirdAnalyst
Species · Maryland · BBS 2025 Release · 1966–2024

Pine Warbler Population Trend in Maryland

All statesForest birds

Pine Warbler in Maryland has surged: up 278% on the route-weighted index since 1968.

+278%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 →
51Routes 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 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 278% 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 2029 — from 6.3 in 2024 to a central estimate of 5.5 (95% range 3.4–7.5). A 5-year backtest shows a typical error of ±22.5%, with 100% of held-out values landing inside the 95% band.

-14%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 →
5.5Projected 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 →
3.4–7.595% 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 →
±22.5%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 2029 — from 6.3 in 2024 to a central estimate of 5.5 (95% range 3.4–7.5). A 5-year backtest shows a typical error of ±22.5%, with 100% 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 →
20255.33.27.3
20265.33.37.4
20275.43.37.4
20285.43.37.5
20295.53.47.5

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 →
Madison6220241966
Cokesbury4320241966
Furnace Town3520242015
Honga1920241966
Forest Grove1920232011
Berlin1520241980
Island Creek1320241991
Oldtown1120241970
Walnut1120241999
Piney Grove1120241995
Sinepuxent1019781966
St. George'S Island1020172015
Snow Hill919761966
Indiantown920141977
Newark820241966
Tall Timbers720141966
Pomonkey720241967
Fruitland619981966
Pomfret520241966
Green Ridge520241995
La Plata420091967
Millington320241967
Melitota320241978
Matthews320241966
Easton320211975

Pine Warbler Population Trend in Other States

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

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