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

Willow Flycatcher Population Trend in Connecticut

All statesAerial insectivores

Willow Flycatcher in Connecticut has increased: up 30% on the route-weighted index since 1969.

+30%Since 1969TrendPercent 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 →
17Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
55YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Willow Flycatcher Trends in ConnecticutNotable 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 Willow Flycatcher in Connecticut. See the full index history below.

Willow Flycatcher Population Forecast in Connecticut

If the recent trend holds, Willow Flycatcher in Connecticut is projected to rise about 36% by 2029 — from 0.56 in 2024 to a central estimate of 0.76 (95% range 0.05–1.5). A 5-year backtest shows a typical error of ±404%, with 40% of held-out values landing inside the 95% band.

+36%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 →
0.76Projected 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 →
0.05–1.595% 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 →
±404%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 Connecticut is projected to rise about 36% by 2029 — from 0.56 in 2024 to a central estimate of 0.76 (95% range 0.05–1.5). A 5-year backtest shows a typical error of ±404%, with 40% of held-out values landing inside the 95% band.19672029
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 →
20250.730.031.4
20260.740.041.4
20270.750.041.4
20280.750.051.5
20290.760.051.5

Willow Flycatcher Survey Routes in Connecticut

Routes recording Willow Flycatcher in Connecticut.
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 →
Warren420111974
Granby420241988
New Hartford319871973
Sherman220181982
Danbury220171968
Mystic120231989
Buckingham120152002
Uncasville120231997
Woodstock120051969
Westbrook119931990
Willimantic120051977
No Woodbury120241967
New Hartford119941994
Long Hill120191974
Mid Haddam120082008
Southington120191979
Woodstock 2120192017

Willow Flycatcher Population Trend in Other States

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

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