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

White-throated Sparrow Population Trend in Connecticut

All statesGeneralists

White-throated Sparrow in Connecticut has fallen sharply: down 64% on the route-weighted index since 1968.

-64%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 →
10Routes 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 →
25YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable White-throated Sparrow 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 declinecomputed 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 →

White-throated Sparrow has fallen sharply in Connecticut: down 64% on the route-weighted index since 1968.

White-throated Sparrow Population Forecast in Connecticut

If the recent trend holds, White-throated Sparrow in Connecticut is projected to fall about 100% by 2027 — from 0.09 in 2022 to a central estimate of 0.00 (95% range 0.00–0.49). A 5-year backtest shows a typical error of ±288.8%, with 80% of held-out values landing inside the 95% band.

-100%Change by 2027TrendPercent 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 →
0.00Projected 2027 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.4995% 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 →
±288.8%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, White-throated Sparrow in Connecticut is projected to fall about 100% by 2027 — from 0.09 in 2022 to a central estimate of 0.00 (95% range 0.00–0.49). A 5-year backtest shows a typical error of ±288.8%, with 80% of held-out values landing inside the 95% band.19662027
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 →
20230.000.000.49
20240.000.000.49
20250.000.000.49
20260.000.000.49
20270.000.000.49

White-throated Sparrow Survey Routes in Connecticut

Routes recording White-throated Sparrow 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 →
New Hartford319971995
Woodstock219871972
Mid Haddam219941974
Mystic120222022
E Hartland119731966
No Woodbury119751974
Greenwich119721972
Danbury119831973
Warren119911972
New Hartford119771972

White-throated Sparrow Population Trend in Other States

mainemassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-dakotapennsylvaniavermontwest-virginiawisconsin

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