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Species · Maryland · BBS 2025 Release · 1966–2024

Louisiana Waterthrush Population Trend in Maryland

All statesForest birds

Louisiana Waterthrush in Maryland has surged: up 249% on the route-weighted index since 1968.

+249%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 →
64Routes 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 Louisiana Waterthrush 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 →

Louisiana Waterthrush has surged in Maryland: up 249% on the route-weighted index since 1968.

Louisiana Waterthrush Population Forecast in Maryland

If the recent trend holds, Louisiana Waterthrush in Maryland is projected to stay roughly flat through 2029, near 0.87 (95% range 0.57–1.2). A 5-year backtest shows a typical error of ±19.2%, with 60% of held-out values landing inside the 95% band.

-6%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 →
0.87Projected 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 →
0.57–1.295% 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 →
±19.2%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, Louisiana Waterthrush in Maryland is projected to stay roughly flat through 2029, near 0.87 (95% range 0.57–1.2). A 5-year backtest shows a typical error of ±19.2%, with 60% 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 →
20250.830.531.1
20260.840.541.1
20270.850.551.2
20280.860.561.2
20290.870.571.2

Louisiana Waterthrush Survey Routes in Maryland

Routes recording Louisiana Waterthrush 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 →
Wolfsville520241966
Piney Grove520241997
Earlton420242014
Accident 2420232018
Floyd320241966
Tall Timbers320131966
Jennings320241995
Green Ridge320241996
Ijamsville320241989
Davidsnville320241984
Smithsburg220141972
Silver Spg219881973
Matthews220211974
Vienna220101967
Sinepuxent219711971
Accident220141993
Wheaton220241991
Island Creek220241992
Mt Nebo119811972
Vindex120141967
Oldtown120231970
Potomac Park120231970
Williamsport120171989
Bald Friar119941994
Olney120231966

Louisiana Waterthrush Population Trend in Other States

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

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