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

Willow Flycatcher Population Trend in Delaware

All statesAerial insectivores

Willow Flycatcher in Delaware has risen sharply: up 63% on the route-weighted index since 1978.

+63%Since 1978
7Routes In State
39Years

Notable Willow Flycatcher Trends in Delaware

long arc increasecomputed index

Willow Flycatcher has risen sharply in Delaware: up 63% on the route-weighted index since 1978.

Willow Flycatcher Population Forecast in Delaware

If the recent trend holds, Willow Flycatcher in Delaware is projected to rise about 126% by 2029 — from 0.20 in 2024 to a central estimate of 0.45 (95% range 0.11–0.80). A 5-year backtest shows a typical error of ±143.5%, with 40% of held-out values landing inside the 95% band.

+126%Change by 2029
0.45Projected 2029 index
0.11–0.8095% range
±143.5%Backtest error
19762029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected index95% low95% high
20250.430.090.78
20260.440.090.79
20270.440.100.79
20280.450.100.79
20290.450.110.80

Willow Flycatcher Survey Routes in Delaware

Routes recording Willow Flycatcher in Delaware.
Mt Pleasant119761976
Wilmington120101978
Harrington120241980
Frederica120101977
Blackbird120231995
Holleyville 2120072007
Georgetown120122004

Willow Flycatcher Population Trend in Other States

alaskaarizonaarkansascaliforniacoloradoconnecticutgeorgiaidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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