BirdAnalyst
Species · BCR 29 · BBS 2026 Release · 1966–2025

Willow Flycatcher In Piedmont

All regionsPiedmontAerial insectivores

Willow Flycatcher in Piedmont has surged: up 93% on the route-weighted index since 1968.

+93%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 →
55Routes 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 →
59YearsYears 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 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 →

Willow Flycatcher has surged in Piedmont: up 93% on the route-weighted index since 1968.

Willow Flycatcher In Piedmont Population Forecast

If the recent trend holds, Willow Flycatcher in Piedmont is projected to rise about 70% by 2030 — from 0.33 in 2025 to a central estimate of 0.55 (95% range 0.14–0.96). A 5-year backtest shows a typical error of ±162.9%, with 40% of held-out values landing inside the 95% band.

+70%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 →
0.55Projected 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 →
0.14–0.9695% 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 →
±162.9%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, Willow Flycatcher in Piedmont is projected to rise about 70% by 2030 — from 0.33 in 2025 to a central estimate of 0.55 (95% range 0.14–0.96). A 5-year backtest shows a typical error of ±162.9%, with 40% of held-out values landing inside the 95% band.19662030
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 →
20260.550.140.96
20270.550.140.96
20280.550.140.96
20290.550.140.96
20300.550.140.96

Routes In Piedmont

Routes recording Willow Flycatcher 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 →
West GrovePENNSYLVANIA141996
Doe RunPENNSYLVANIA72025
Pleasant ValMARYLAND42025
Bachman MillMARYLAND32025
EkloMARYLAND32018
CrotonNEW-JERSEY32007
Mt Gretna 2PENNSYLVANIA32019
PartlowVIRGINIA31980
EmmitsburgMARYLAND22025
OlneyMARYLAND22025
WarfieldsbrgMARYLAND22025
RandallstownMARYLAND22013
IjamsvilleMARYLAND22025
MadonnaMARYLAND22019
GilletteNEW-JERSEY22025
CollegevillePENNSYLVANIA22024
ShrewsburyPENNSYLVANIA22023
AthensGEORGIA11993
Holly SprsGEORGIA11980
Silver SpgMARYLAND11988
FowblesburgMARYLAND12016
Upper XrdsMARYLAND12007
Van BibberMARYLAND12004
TheodoreMARYLAND12012
WheatonMARYLAND11999

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