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Species · Connecticut · BBS 2025 Release · 1966–2024

Black-and-white Warbler Population Trend in Connecticut

All statesForest birds

Black-and-white Warbler in Connecticut has declined: down 42% on the route-weighted index since 1968.

-42%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 →
20Routes 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 →
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 Black-and-white 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 →

No notable trend signals for Black-and-white Warbler in Connecticut. See the full index history below.

Black-and-white Warbler Population Forecast in Connecticut

If the recent trend holds, Black-and-white Warbler in Connecticut is projected to fall about 14% by 2029 — from 2.1 in 2024 to a central estimate of 1.8 (95% range 0.00–3.7). A 5-year backtest shows a typical error of ±38.9%, with 100% of held-out values landing inside the 95% band.

-14%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 →
1.8Projected 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 →
0.00–3.795% 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 →
±38.9%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, Black-and-white Warbler in Connecticut is projected to fall about 14% by 2029 — from 2.1 in 2024 to a central estimate of 1.8 (95% range 0.00–3.7). A 5-year backtest shows a typical error of ±38.9%, with 100% 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 →
20251.90.083.8
20261.90.053.8
20271.90.023.7
20281.90.003.7
20291.80.003.7

Black-and-white Warbler Survey Routes in Connecticut

Routes recording Black-and-white 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 →
Warren2520111972
Granby820241988
E Hartland519921967
New Hartford519871972
Woodstock 2520242016
Woodstock420071968
Willimantic420181967
Warren 2320242012
Mystic220041973
No Woodbury220221967
Danbury220131968
New Hartford220241994
Buckingham120051966
Uncasville120211973
Westbrook119981969
Sherman120151973
Greenwich119971967
Long Hill120191972
Mid Haddam120241973
Southington120191973

Black-and-white Warbler Population Trend in Other States

alabamaarkansascaliforniadelawaregeorgiaillinoisindianakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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