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

Blue-winged Warbler In Piedmont

All regionsPiedmontForest birds

Blue-winged Warbler in Piedmont has collapsed: down 81% on the route-weighted index since 1972.

-81%Since 1972TrendPercent 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 →
34Routes 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 →
50YearsYears 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 →

long arc declinecomputed 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 →

Blue-winged Warbler has collapsed in Piedmont: down 81% on the route-weighted index since 1972.

Blue-winged Warbler In Piedmont Population Forecast

If the recent trend holds, Blue-winged Warbler in Piedmont is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.10). A 5-year backtest shows a typical error of ±44.9%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.00Projected 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 →
0.00–0.1095% 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 →
±44.9%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, Blue-winged Warbler in Piedmont is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.10). A 5-year backtest shows a typical error of ±44.9%, 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 →
20250.010.000.10
20260.010.000.10
20270.000.000.10
20280.000.000.10
20290.000.000.10

Routes In Piedmont

Routes recording Blue-winged Warbler 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 →
JacobusPENNSYLVANIA141997
West GrovePENNSYLVANIA31996
Holly SprsGEORGIA21978
GilletteNEW-JERSEY22024
MillervilleALABAMA11973
BaldwinGEORGIA11970
BowdonGEORGIA11990
OlneyMARYLAND12024
Pleasant ValMARYLAND11987
Bachman MillMARYLAND12007
EkloMARYLAND12016
RandallstownMARYLAND12005
TheodoreMARYLAND11988
IjamsvilleMARYLAND12005
MadonnaMARYLAND12014
EarltonMARYLAND12014
SandbrookNEW-JERSEY12017
CrotonNEW-JERSEY12007
PottersvilleNEW-JERSEY11998
Croton 2NEW-JERSEY12018
CallNORTH-CAROLINA11970
PottstownPENNSYLVANIA11979
CollegevillePENNSYLVANIA12011
LabottPENNSYLVANIA11980
Doe RunPENNSYLVANIA11988

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