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

Alder Flycatcher Population Trend in Connecticut

All statesAerial insectivores

Alder Flycatcher in Connecticut has risen sharply: up 66% on the route-weighted index since 1976.

+66%Since 1976TrendPercent 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 →
13Routes 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 →
42YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Alder 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 →

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 →

Alder Flycatcher has risen sharply in Connecticut: up 65% on the route-weighted index since 1976.

Alder Flycatcher Population Forecast in Connecticut

If the recent trend holds, Alder Flycatcher in Connecticut is projected to stay roughly flat through 2029, near 0.37 (95% range 0.00–0.94). A 5-year backtest shows a typical error of ±84.4%, with 100% of held-out values landing inside the 95% band.

+10%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 →
0.37Projected 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 →
0.00–0.9495% 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 →
±84.4%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, Alder Flycatcher in Connecticut is projected to stay roughly flat through 2029, near 0.37 (95% range 0.00–0.94). A 5-year backtest shows a typical error of ±84.4%, with 100% of held-out values landing inside the 95% band.19742029
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 →
20250.360.000.94
20260.360.000.94
20270.360.000.94
20280.360.000.94
20290.370.000.94

Alder Flycatcher Survey Routes in Connecticut

Routes recording Alder 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
Buckingham220092004
Woodstock 2220242017
New Hartford120231996
Willimantic119961974
No Woodbury120121982
Sherman120052005
Long Hill119741974
Mid Haddam119961990
Southington119741974
New Hartford119871981
Warren 2120242024
Granby120231990

Alder Flycatcher Population Trend in Other States

alaskaidahoillinoisindianaiowamainemarylandmassachusettsmichiganminnesotamontananew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniasouth-dakotavermontvirginiawashingtonwest-virginiawisconsin

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