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

Blue-winged Teal Population Trend in Wisconsin

All statesWaterfowl

Blue-winged Teal in Wisconsin has collapsed: down 85% on the route-weighted index since 1968.

-85%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 →
67Routes 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 Blue-winged Teal Trends in WisconsinNotable 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 →

Blue-winged Teal has collapsed in Wisconsin: down 85% on the route-weighted index since 1968.

Blue-winged Teal Population Forecast in Wisconsin

If the recent trend holds, Blue-winged Teal in Wisconsin is projected to fall about 100% by 2029 — from 0.22 in 2024 to a central estimate of 0.00 (95% range 0.00–0.80). A 5-year backtest shows a typical error of ±205.4%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–0.8095% 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 →
±205.4%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-winged Teal in Wisconsin is projected to fall about 100% by 2029 — from 0.22 in 2024 to a central estimate of 0.00 (95% range 0.00–0.80). A 5-year backtest shows a typical error of ±205.4%, 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 →
20250.000.000.80
20260.000.000.80
20270.000.000.80
20280.000.000.80
20290.000.000.80

Blue-winged Teal Survey Routes in Wisconsin

Routes recording Blue-winged Teal in Wisconsin.
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 →
Union Twp1219871987
Clintonville620081974
Beloit620112011
Hudson520241966
Casco520231973
Pardeeville419931973
Holland420242004
Loraine320161967
Trempealeau319891989
Verona320092004
Wiota320081973
Cumberland220131970
Couderay219801980
Irma220031973
Meridean220052005
Hollister220041979
Washington I219891967
Esdaile219891973
Wis Rapids220191975
Oconto Falls220091972
Omro220001966
Bashaw220092004
Grimms220052003
Princeton219901966
Rolling Pr220241966

Blue-winged Teal Population Trend in Other States

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