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

Pine Warbler Population Trend in Connecticut

All statesForest birds

Pine Warbler in Connecticut has surged: up 32× on the route-weighted index since 1980.

32×Since 1980TrendPercent 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 →
19Routes 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 →
43YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Pine Warbler 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 →

Pine Warbler has surged in Connecticut: up 32× on the route-weighted index since 1980.

Pine Warbler Population Forecast in Connecticut

If the recent trend holds, Pine Warbler in Connecticut is projected to rise about 17% by 2029 — from 2.9 in 2024 to a central estimate of 3.4 (95% range 2.7–4.1). A 5-year backtest shows a typical error of ±14.7%, with 80% of held-out values landing inside the 95% band.

+17%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 →
3.4Projected 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 →
2.7–4.195% 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 →
±14.7%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, Pine Warbler in Connecticut is projected to rise about 17% by 2029 — from 2.9 in 2024 to a central estimate of 3.4 (95% range 2.7–4.1). A 5-year backtest shows a typical error of ±14.7%, with 80% of held-out values landing inside the 95% band.19752029
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 →
20253.12.43.8
20263.22.43.9
20273.22.54.0
20283.32.64.1
20293.42.74.1

Pine Warbler Survey Routes in Connecticut

Routes recording Pine Warbler 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 →
Warren720111978
Uncasville520241990
Woodstock520071983
Willimantic520181975
Warren 2520242012
Granby520241995
Mystic320231987
No Woodbury320211995
New Hartford320241994
Woodstock 2320242016
Buckingham220222010
Sherman220151998
Greenwich220141989
Mid Haddam220241980
Southington220242010
New Hartford219851985
Westbrook120241993
Danbury120142013
Long Hill120192005

Pine Warbler Population Trend in Other States

alabamaarkansasdelawarefloridageorgiaillinoisindianakentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniarhode-islandsouth-carolinatennesseetexasvermontvirginiawest-virginiawisconsin

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