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

Winter Wren Population Trend in Pennsylvania

All statesForest birds

Winter Wren in Pennsylvania has surged: up 13× on the route-weighted index since 1976.

13×Since 1976TrendPercent 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 →
58Routes 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 →
49YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Winter Wren Trends in PennsylvaniaNotable 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 →

Winter Wren has surged in Pennsylvania: up 13× on the route-weighted index since 1976.

Winter Wren Population Forecast in Pennsylvania

If the recent trend holds, Winter Wren in Pennsylvania is projected to stay roughly flat through 2029, near 0.38 (95% range 0.14–0.62). A 5-year backtest shows a typical error of ±29.4%, with 100% of held-out values landing inside the 95% band.

-9%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 →
0.38Projected 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 →
0.14–0.6295% 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 →
±29.4%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, Winter Wren in Pennsylvania is projected to stay roughly flat through 2029, near 0.38 (95% range 0.14–0.62). A 5-year backtest shows a typical error of ±29.4%, with 100% of held-out values landing inside the 95% band.19702029
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 →
20250.360.110.60
20260.360.120.61
20270.370.120.61
20280.370.130.62
20290.380.140.62

Winter Wren Survey Routes in Pennsylvania

Routes recording Winter Wren in Pennsylvania.
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 →
Russell City620241974
Poyntelle520241974
Roulette 2520242022
Odin420241991
Roulette420211980
Susquehanna420231976
Ellenton320241983
Berwick320001994
Rasselas320211989
Logue320231976
Honesdale320231990
Teepleville219931993
Lynch220241970
N Pine Grove220231995
Little Marsh220211995
Cherry Sprs220231991
Mawr Glen220231983
Rush220231980
Canadensis220241997
Ansonia220242003
Ltl Pine Cr220231990
Duboistown220241987
Wyalusing119971989
Whig Hill120131990
Rothrock Sf120141992

Winter Wren Population Trend in Other States

connecticutmainemarylandmassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-carolinaohiotennesseevermontvirginiawest-virginiawisconsin

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