BirdAnalyst
Species · Utah · BBS 2026 Release · 1966–2025

Common Merganser Population Trend in Utah

All statesWaterfowl

Common Merganser in Utah has edged down: down 11% on the route-weighted index since 1995.

-11%Since 1995TrendPercent 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 →
10Routes 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 →
19YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Common Merganser Trends in UtahNotable 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 Common Merganser in Utah. See the full index history below.

Common Merganser Population Forecast in Utah

If the recent trend holds, Common Merganser in Utah is projected to fall about 56% by 2030 — from 0.09 in 2025 to a central estimate of 0.04 (95% range 0.00–0.12). A 5-year backtest shows a typical error of ±59%, with 100% of held-out values landing inside the 95% band.

-56%Change by 2030TrendPercent 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 →
0.04Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.1295% 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 →
±59%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, Common Merganser in Utah is projected to fall about 56% by 2030 — from 0.09 in 2025 to a central estimate of 0.04 (95% range 0.00–0.12). A 5-year backtest shows a typical error of ±59%, with 100% of held-out values landing inside the 95% band.19902030
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 →
20260.040.000.12
20270.040.000.12
20280.040.000.12
20290.040.000.12
20300.040.000.12

Common Merganser Survey Routes in Utah

Routes recording Common Merganser in Utah.
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 →
Ferron620212018
M Warner Res420252025
Jensen320072007
Kamas320152004
Lynn220251990
Neponset Res120031995
Lost Cr. Res120152015
Delta119941994
Hanna120242000
Aneth120102010

Common Merganser Population Trend in Other States

alaskaarizonacaliforniacoloradoconnecticutidahomainemarylandmassachusettsmichiganminnesotamontananevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-dakotaohiooregonpennsylvaniasouth-dakotavermontvirginiawashingtonwest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.