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Species · BCR 19 · BBS 2025 Release · 1966–2024

Gadwall In Central Mixed Grass Prairie

All regionsCentral Mixed Grass PrairieWaterfowl

Gadwall in Central Mixed Grass Prairie has collapsed: down 79% on the route-weighted index since 1969.

-79%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 →
17Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
52YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 →

Gadwall has collapsed in Central Mixed Grass Prairie: down 79% on the route-weighted index since 1969.

Gadwall In Central Mixed Grass Prairie Population Forecast

If the recent trend holds, Gadwall in Central Mixed Grass Prairie is projected to fall about 93% by 2029 — from 0.12 in 2024 to a central estimate of 0.01 (95% range 0.00–0.26). A 5-year backtest shows a typical error of ±116.8%, with 100% of held-out values landing inside the 95% band.

-93%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 →
0.01Projected 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 →
0.00–0.2695% 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 →
±116.8%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, Gadwall in Central Mixed Grass Prairie is projected to fall about 93% by 2029 — from 0.12 in 2024 to a central estimate of 0.01 (95% range 0.00–0.26). A 5-year backtest shows a typical error of ±116.8%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20250.020.000.28
20260.020.000.27
20270.020.000.27
20280.010.000.27
20290.010.000.26

Routes In Central Mixed Grass Prairie

Routes recording Gadwall in Central Mixed Grass Prairie.
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 →
St JohnKANSAS61969
Piester LakeNEBRASKA62016
AlbertKANSAS41987
KennedyNEBRASKA42024
ArthurNEBRASKA42024
Crescent LkNEBRASKA42016
Swan LakeNEBRASKA32021
LeovilleKANSAS21977
LoganKANSAS21977
RinggoldNEBRASKA22005
Wheeler CoNEBRASKA22022
NenzelNEBRASKA22021
WeinertTEXAS21993
MisslerKANSAS12005
TableNEBRASKA12017
GordonNEBRASKA12013
BrownleeNEBRASKA12018

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