BirdAnalyst
Species · BCR 22 · BBS 2025 Release · 1966–2024

Hooded Merganser In Eastern Tallgrass Prairie

All regionsEastern Tallgrass PrairieWaterfowl

Hooded Merganser in Eastern Tallgrass Prairie has fallen sharply: down 75% on the route-weighted index since 1992.

-75%Since 1992TrendPercent 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 →
30Routes 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 →
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 SignalsNotable 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 Hooded Merganser in Eastern Tallgrass Prairie. See the full index history below.

Hooded Merganser In Eastern Tallgrass Prairie Population Forecast

If the recent trend holds, Hooded Merganser in Eastern Tallgrass Prairie is projected to stay roughly flat through 2029, near 0.02 (95% range 0.00–0.07). A 5-year backtest shows a typical error of ±390.9%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.02Projected 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 →
0.00–0.0795% 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 →
±390.9%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, Hooded Merganser in Eastern Tallgrass Prairie is projected to stay roughly flat through 2029, near 0.02 (95% range 0.00–0.07). A 5-year backtest shows a typical error of ±390.9%, with 100% of held-out values landing inside the 95% band.19782029
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 →
20250.020.000.07
20260.020.000.07
20270.020.000.07
20280.020.000.07
20290.020.000.07

Routes In Eastern Tallgrass Prairie

Routes recording Hooded Merganser in Eastern Tallgrass 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 →
CameronILLINOIS61989
Troy GroveILLINOIS42018
Sioux CityIOWA42006
Camp PointILLINOIS32011
NewarkILLINOIS22010
GulfportILLINOIS22014
Concord WestILLINOIS22010
AliceIOWA21994
PiersonIOWA22019
LakevilleMINNESOTA22014
IrvingtonNEBRASKA22004
MinonkILLINOIS12004
PawneeILLINOIS11998
JamestownILLINOIS12012
BeaucoupILLINOIS12012
OlneyILLINOIS12017
SenecaILLINOIS12024
PaysonILLINOIS12016
Grape CreekILLINOIS12022
DudleyvilleILLINOIS12010
KellILLINOIS12006
Kankakee SandsINDIANA12008
GazaIOWA11992
Rock ValleyIOWA11993
Ash CreekMINNESOTA12013

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