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Species · Massachusetts · BBS 2026 Release · 1966–2025

Louisiana Waterthrush Population Trend in Massachusetts

All statesForest birds

Louisiana Waterthrush in Massachusetts has surged: up 468% on the route-weighted index since 1969.

+468%Since 1969TrendPercent 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 →
16Routes 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 →
56YearsYears 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 MassachusettsNotable 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 Massachusetts: up 468% on the route-weighted index since 1969.

Louisiana Waterthrush Population Forecast in Massachusetts

If the recent trend holds, Louisiana Waterthrush in Massachusetts is projected to fall about 39% by 2030 — from 0.50 in 2025 to a central estimate of 0.31 (95% range 0.00–0.62). A 5-year backtest shows a typical error of ±46.3%, with 80% of held-out values landing inside the 95% band.

-39%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 →
0.31Projected 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 →
0.00–0.6295% 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 →
±46.3%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 Massachusetts is projected to fall about 39% by 2030 — from 0.50 in 2025 to a central estimate of 0.31 (95% range 0.00–0.62). A 5-year backtest shows a typical error of ±46.3%, with 80% of held-out values landing inside the 95% band.19672030
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 →
20260.300.000.61
20270.300.000.61
20280.300.000.61
20290.310.000.62
20300.310.000.62

Louisiana Waterthrush Survey Routes in Massachusetts

Routes recording Louisiana Waterthrush in Massachusetts.
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 →
Belchertown320251968
Monterey320252019
Warren220051969
S Barre220221981
Ware River120182018
Newburyport119861986
N Oxford119951995
N Orange120251971
Cummington120131970
Chesterfield120251967
Holden120211979
Pittsfield120001970
Sheffield120221970
Warren 2120242012
Cummington 2120242015
Hancock120151999

Louisiana Waterthrush Population Trend in Other States

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

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