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Species · Maryland · BBS 2026 Release · 1966–2025

Prairie Warbler Population Trend in Maryland

All statesForest birds

Prairie Warbler in Maryland has fallen sharply: down 71% on the route-weighted index since 1968.

-71%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 →
71Routes 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 Prairie 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 declinecomputed 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 →

Prairie Warbler has fallen sharply in Maryland: down 71% on the route-weighted index since 1968.

Prairie Warbler Population Forecast in Maryland

If the recent trend holds, Prairie Warbler in Maryland is projected to stay roughly flat through 2030, near 0.73 (95% range 0.06–1.4). A 5-year backtest shows a typical error of ±16.5%, with 100% of held-out values landing inside the 95% band.

-1%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 →
0.73Projected 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 →
0.06–1.495% 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 →
±16.5%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, Prairie Warbler in Maryland is projected to stay roughly flat through 2030, near 0.73 (95% range 0.06–1.4). A 5-year backtest shows a typical error of ±16.5%, 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 →
20260.830.171.5
20270.810.141.5
20280.780.121.4
20290.760.091.4
20300.730.061.4

Prairie Warbler Survey Routes in Maryland

Routes recording Prairie 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 →
Cokesbury1120251966
Oldtown520251970
Cheltenham520031966
Walnut520242001
Pt Republic419891966
Harmony319741966
Snow Hill319741966
Furnace Town320222015
Floyd219831971
Jones219941990
Hughesville220251966
Easton219741972
Newark220251966
Forest Grove220232011
Mt Nebo119821969
Vindex119951967
Potomac Park120181980
Williamsport120152001
Smithsburg119981990
Wolfsville119871987
Emmitsburg120221969
Silver Spg119891972
Olney120231966
Norwood119851966
Warfieldsbrg120162009

Prairie Warbler Population Trend in Other States

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

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