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Species · Connecticut · BBS 2025 Release · 1966–2024

Mute Swan Population Trend in Connecticut

All statesWaterfowl

Mute Swan in Connecticut has edged up: up 11% on the route-weighted index since 1979.

+11%Since 1979TrendPercent 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 →
8Routes 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 →
23YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Mute Swan 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 Mute Swan in Connecticut. See the full index history below.

Mute Swan Population Forecast in Connecticut

If the recent trend holds, Mute Swan in Connecticut is projected to fall about 13% by 2024 — from 0.23 in 2019 to a central estimate of 0.20 (95% range 0.01–0.39). A 5-year backtest shows a typical error of ±35.3%, with 100% of held-out values landing inside the 95% band.

-13%Change by 2024TrendPercent 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 →
0.20Projected 2024 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.01–0.3995% 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 →
±35.3%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, Mute Swan in Connecticut is projected to fall about 13% by 2024 — from 0.23 in 2019 to a central estimate of 0.20 (95% range 0.01–0.39). A 5-year backtest shows a typical error of ±35.3%, with 100% of held-out values landing inside the 95% band.19772024
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 →
20200.200.010.39
20210.200.010.39
20220.200.010.39
20230.200.010.39
20240.200.010.39

Mute Swan Survey Routes in Connecticut

Routes recording Mute Swan 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 →
Mystic319811977
Danbury320191980
Uncasville220112011
Westbrook219931986
Sherman220071983
Greenwich220181999
Mid Haddam219841984
Warren119941994

Mute Swan Population Trend in Other States

californiadelawareillinoisindianakentuckymarylandmassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorkohiopennsylvaniarhode-islandvirginiawisconsin

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