BirdAnalyst
Species · BCR 29 · BBS 2025 Release · 1966–2024

Northern House Wren In Piedmont

All regionsPiedmontForest birds

Northern House Wren in Piedmont has declined: down 31% on the route-weighted index since 1968.

-31%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 →
137Routes In RegionSurvey 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 SignalsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Northern House Wren in Piedmont. See the full index history below.

Northern House Wren In Piedmont Population Forecast

If the recent trend holds, Northern House Wren in Piedmont is projected to stay roughly flat through 2029, near 5.3 (95% range 3.4–7.2). A 5-year backtest shows a typical error of ±7.1%, with 100% of held-out values landing inside the 95% band.

+2%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 →
5.3Projected 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 →
3.4–7.295% 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 →
±7.1%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 House Wren in Piedmont is projected to stay roughly flat through 2029, near 5.3 (95% range 3.4–7.2). A 5-year backtest shows a typical error of ±7.1%, 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 →
20255.43.67.3
20265.43.57.3
20275.43.57.2
20285.33.57.2
20295.33.47.2

Routes In Piedmont

Routes recording Northern House Wren in Piedmont.
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 →
EmmitsburgMARYLAND522024
WheatonMARYLAND422024
Croton 2NEW-JERSEY392024
EarltonMARYLAND312024
CollegevillePENNSYLVANIA312024
EkloMARYLAND302018
OlneyMARYLAND272024
MadonnaMARYLAND262022
West GrovePENNSYLVANIA241996
PottstownPENNSYLVANIA231987
Doe RunPENNSYLVANIA222024
WarfieldsbrgMARYLAND202024
GilletteNEW-JERSEY192024
Mt Gretna 2PENNSYLVANIA192022
RandallstownMARYLAND182013
BendersvillePENNSYLVANIA182024
IjamsvilleMARYLAND172024
SandbrookNEW-JERSEY172024
JacobusPENNSYLVANIA172024
AspersPENNSYLVANIA151989
Mount JoyPENNSYLVANIA152024
SchwenksvillPENNSYLVANIA152024
ChathamPENNSYLVANIA152024
GatchelvillePENNSYLVANIA141990
Silver SpgMARYLAND131989

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