BirdAnalyst
Species · Maryland · BBS 2026 Release · 1966–2025

Northern Parula Population Trend in Maryland

All statesForest birds

Northern Parula in Maryland has surged: up 180% on the route-weighted index since 1968.

+180%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 →
72Routes 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 Northern Parula 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 →

Northern Parula has surged in Maryland: up 180% on the route-weighted index since 1968.

Northern Parula Population Forecast in Maryland

If the recent trend holds, Northern Parula in Maryland is projected to rise about 14% by 2030 — from 3.1 in 2025 to a central estimate of 3.6 (95% range 3.0–4.1). A 5-year backtest shows a typical error of ±7.9%, 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 →
3.6Projected 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 →
3.0–4.195% 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 →
±7.9%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, Northern Parula in Maryland is projected to rise about 14% by 2030 — from 3.1 in 2025 to a central estimate of 3.6 (95% range 3.0–4.1). A 5-year backtest shows a typical error of ±7.9%, 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 →
20263.42.83.9
20273.42.94.0
20283.52.94.0
20293.53.04.1
20303.63.04.1

Northern Parula Survey Routes in Maryland

Routes recording Northern Parula 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 →
Pomonkey2720251966
Island Creek2220251991
Pomfret1120241966
Pt Republic1019891966
Jessup1020252013
Earlton1020242014
Broomes Isl819961966
Davidsnville820251982
Nottingham820252005
Forest Grove720232011
Hughesville620251966
Jennings620251995
Pr Frederick620251991
Olney520251966
La Plata520091966
Williamsport420252001
Tall Timbers420141966
Wheaton420241990
Oldtown320251970
Van Bibber320131966
Piney Grove320231995
Accident320171992
Ijamsville320251986
Silver Spg219861967
Norwood220111973

Northern Parula Population Trend in Other States

alabamaarkansascaliforniaconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemassachusettsmichiganminnesotamississippimissourinebraskanew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsin

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