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

Willow Flycatcher In Piedmont

All regionsPiedmontAerial insectivores

Willow Flycatcher in Piedmont has risen sharply: up 65% on the route-weighted index since 1968.

+65%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 →
54Routes 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 →

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 risen sharply in Piedmont: up 65% on the route-weighted index since 1968.

Forecast

If the recent trend holds, Willow Flycatcher in Piedmont is projected to rise about 123% by 2029 — from 0.26 in 2024 to a central estimate of 0.57 (95% range 0.16–0.98). A 5-year backtest shows a typical error of ±169%, with 20% of held-out values landing inside the 95% band.

+123%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 →
0.57Projected 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 →
0.16–0.9895% 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 →
±169%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 123% by 2029 — from 0.26 in 2024 to a central estimate of 0.57 (95% range 0.16–0.98). A 5-year backtest shows a typical error of ±169%, with 20% 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 →
20250.570.150.98
20260.570.160.98
20270.570.160.98
20280.570.160.98
20290.570.160.98

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
EmmitsburgMARYLAND52024
WarfieldsbrgMARYLAND32018
EkloMARYLAND32018
CrotonNEW-JERSEY32007
GilletteNEW-JERSEY32024
Doe RunPENNSYLVANIA32024
Mt Gretna 2PENNSYLVANIA32019
PartlowVIRGINIA31980
OlneyMARYLAND22024
Pleasant ValMARYLAND22024
RandallstownMARYLAND22013
MadonnaMARYLAND22019
SandbrookNEW-JERSEY22022
Croton 2NEW-JERSEY22023
CollegevillePENNSYLVANIA22024
ShrewsburyPENNSYLVANIA22023
ChathamPENNSYLVANIA22024
AthensGEORGIA11993
Holly SprsGEORGIA11980
Silver SpgMARYLAND11988
Bachman MillMARYLAND12024
FowblesburgMARYLAND12016
Upper XrdsMARYLAND12007
Van BibberMARYLAND12004

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