BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Northern Waterthrush

ParulidaeForest birdsParkesia noveboracensis

Northern Waterthrush has surged: up 297% on the route-weighted index since 1968.

+297%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 →
628RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Northern Waterthrush

The Northern Waterthrush (Parkesia noveboracensis) is a North American member of the Wood-Warblers (Parulidae). In this analysis it is grouped with the forest birds.

Size
4.5–5.5 in long (11–14 cm) — a small, active songbird (typical for the family)
Habitat
Woodlands and forest edges, including wooded suburbs and parks.
Diet
Insects and spiders gleaned from foliage and bark, with seeds and berries in season.
Range
Recorded on 628 Breeding Bird Survey routes across 23 states, most concentrated in the Atlantic Northern Forest.
Family
Parulidae · Forest birds

Notable Northern Waterthrush TrendsNotable 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 Waterthrush has surged in surveyed states: up 297% on the route-weighted index since 1968.

Northern Waterthrush Population Forecast

If the recent trend holds, Northern Waterthrush is projected to stay roughly flat through 2029, near 0.43 (95% range 0.28–0.58). A 5-year backtest shows a typical error of ±10.5%, with 100% of held-out values landing inside the 95% band.

+5%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 →
0.43Projected 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 →
0.28–0.5895% 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 →
±10.5%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, Northern Waterthrush is projected to stay roughly flat through 2029, near 0.43 (95% range 0.28–0.58). A 5-year backtest shows a typical error of ±10.5%, 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 →
20250.410.260.56
20260.410.260.56
20270.420.270.57
20280.420.280.57
20290.430.280.58

Where the Northern Waterthrush Is Detected

BBS routes recording Northern Waterthrush, sized by most recent count.

Northern Waterthrush Population Trend by State

Northern Waterthrush population trend by state.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Alaska+180%1975104
Connecticut-54%196916
Idaho-28%198313
Maine-64%196872
Marylandinsufficient datan/a3
Massachusetts+256%197019
Michigan-68%196855
Minnesota+378%196936
Montana+592%197343
New Hampshire-55%196826
New Jersey-36%19808
New York+11%196888
North Carolinainsufficient datan/a1
North Dakotainsufficient datan/a2
Ohioinsufficient datan/a1
Pennsylvania-61%196842
Rhode Island+71%19754
Vermont+45%196923
Virginiainsufficient datan/a2
Washington+48%19897
West Virginia+149%197611
Wisconsin+382%196851
Wyominginsufficient datan/a1

Northern Waterthrush Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Northern Waterthrush population trend by Bird Conservation Region.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
BCR 2-55%198719
BCR 3+570%19973
BCR 4+5%197663
Northern Pacific Rainforest+90%198319
Northern Rockies+433%197361
Prairie Potholes+546%19815
Boreal Hardwood Transition+34%1968103
Lower Great Lakes / St. Lawrence Plain+71%196846
Atlantic Northern Forest-37%1968148
Prairie Hardwood Transition+171%196836
Appalachian Mountains-4%196884
New England / Mid-Atlantic Coast+47%196837

Northern Waterthrush Conservation Status

Our route-weighted index shows it up about 297% since 1968.

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.