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

Northern Parula Population Trend in Maryland

All statesForest birds

Northern Parula in Maryland has surged: up 172% on the route-weighted index since 1968.

+172%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 →
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 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 172% 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 stay roughly flat through 2029, near 3.5 (95% range 3.0–4.1). A 5-year backtest shows a typical error of ±8.1%, with 100% of held-out values landing inside the 95% band.

+7%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 →
3.5Projected 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 →
3.0–4.195% 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 →
±8.1%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 stay roughly flat through 2029, near 3.5 (95% range 3.0–4.1). A 5-year backtest shows a typical error of ±8.1%, 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 →
20253.32.83.9
20263.42.83.9
20273.42.94.0
20283.52.94.0
20293.53.04.1

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 →
Pomonkey3520241966
Island Creek1820241991
Hughesville1320241966
Pomfret1120241966
Jennings1120241995
Pt Republic1019891966
Earlton1020242014
Broomes Isl819961966
Forest Grove720232011
Davidsnville720241982
Nottingham720242005
La Plata520091966
Olney420241966
Tall Timbers420141966
Furnace Town420232015
Wheaton420241990
Williamsport320242001
Van Bibber320131966
Piney Grove320231995
Accident320171992
Silver Spg219861967
Norwood220111973
Largo219801966
Theodore220131968
Cokesbury220212008

Northern Parula Population Trend in Other States

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

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