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Species · Connecticut · BBS 2025 Release · 1966–2024

American Black Duck Population Trend in Connecticut

All statesWaterfowl

American Black Duck in Connecticut has collapsed: down 88% on the route-weighted index since 1969.

-88%Since 1969TrendPercent 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 →
11Routes 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 American Black Duck 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 →

American Black Duck has collapsed in Connecticut: down 88% on the route-weighted index since 1969.

American Black Duck Population Forecast in Connecticut

If the recent trend holds, American Black Duck in Connecticut is projected to fall about 100% by 2022 — from 0.07 in 2017 to a central estimate of 0.00 (95% range 0.00–1.2). A 5-year backtest shows a typical error of ±397.5%, with 100% of held-out values landing inside the 95% band.

-100%Change by 2022TrendPercent 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 2022 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–1.295% 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 →
±397.5%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, American Black Duck in Connecticut is projected to fall about 100% by 2022 — from 0.07 in 2017 to a central estimate of 0.00 (95% range 0.00–1.2). A 5-year backtest shows a typical error of ±397.5%, with 100% of held-out values landing inside the 95% band.19672022
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 →
20180.000.001.2
20190.000.001.2
20200.000.001.2
20210.000.001.2
20220.000.001.2

American Black Duck Survey Routes in Connecticut

Routes recording American Black Duck 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 →
Westbrook919911981
Willimantic519701969
E Hartland219691968
Danbury219711971
Mystic120171981
Uncasville119821982
Woodstock119791968
No Woodbury119701969
Sherman119891972
Greenwich119751967
Mid Haddam119941983

American Black Duck Population Trend in Other States

alabamadelawareindianamainemarylandmassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiopennsylvaniarhode-islandvermontvirginiawest-virginiawisconsin

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