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Species · Connecticut · BBS 2025 Release · 1966–2024

Blue-headed Vireo Population Trend in Connecticut

All statesForest birds

Blue-headed Vireo in Connecticut has increased: up 27% on the route-weighted index since 1974.

+27%Since 1974TrendPercent 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 →
16Routes 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 →
51YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Blue-headed Vireo 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 Blue-headed Vireo in Connecticut. See the full index history below.

Blue-headed Vireo Population Forecast in Connecticut

If the recent trend holds, Blue-headed Vireo in Connecticut is projected to rise about 67% by 2029 — from 0.33 in 2024 to a central estimate of 0.56 (95% range 0.02–1.1). A 5-year backtest shows a typical error of ±87.5%, with 100% of held-out values landing inside the 95% band.

+67%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 →
0.56Projected 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 →
0.02–1.195% 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 →
±87.5%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, Blue-headed Vireo in Connecticut is projected to rise about 67% by 2029 — from 0.33 in 2024 to a central estimate of 0.56 (95% range 0.02–1.1). A 5-year backtest shows a typical error of ±87.5%, with 100% of held-out values landing inside the 95% band.19722029
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 →
20250.530.001.1
20260.540.011.1
20270.540.011.1
20280.550.021.1
20290.560.021.1

Blue-headed Vireo Survey Routes in Connecticut

Routes recording Blue-headed Vireo 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 →
Warren520111973
Sherman320191982
Greenwich219751972
Mystic119961996
E Hartland119911988
Buckingham120112000
Woodstock119911982
New Hartford120241994
No Woodbury120221992
Danbury119981972
Long Hill119881974
Woodstock 2120212017
Southington119951990
New Hartford119871972
Warren 2120242012
Granby120241988

Blue-headed Vireo Population Trend in Other States

alabamageorgiakentuckymainemarylandmassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiopennsylvaniarhode-islandsouth-carolinatennesseevermontvirginiawest-virginiawisconsin

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