BirdAnalyst
Species · North Dakota · BBS 2025 Release · 1966–2024

Horned Grebe Population Trend in North Dakota

All statesWetland birds

Horned Grebe in North Dakota has declined: down 32% on the route-weighted index since 1971.

-32%Since 1971TrendPercent 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 →
19Routes 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 →
36YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Horned Grebe Trends in North DakotaNotable 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 Horned Grebe in North Dakota. See the full index history below.

Horned Grebe Population Forecast in North Dakota

If the recent trend holds, Horned Grebe in North Dakota is projected to rise about 14% by 2029 — from 0.07 in 2024 to a central estimate of 0.08 (95% range 0.00–0.26). A 5-year backtest shows a typical error of ±181.8%, with 100% of held-out values landing inside the 95% band.

+14%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 →
0.08Projected 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 →
±181.8%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, Horned Grebe in North Dakota is projected to rise about 14% by 2029 — from 0.07 in 2024 to a central estimate of 0.08 (95% range 0.00–0.26). A 5-year backtest shows a typical error of ±181.8%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20250.090.000.26
20260.090.000.26
20270.090.000.26
20280.090.000.26
20290.080.000.26

Horned Grebe Survey Routes in North Dakota

Routes recording Horned Grebe in North Dakota.
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 →
Webster319971996
Cooperstown219961973
Horsehead Lk220101982
Buchanan220221969
Bowesmont219681968
Rolla220031969
Powers Lake220061982
Douglas Crk220132013
Turtle Mtns220241980
Lakota 2220152011
Danzig119951995
Lakota119981968
Niles120131995
Regan119801978
Carpio120101979
Loraine119951995
Wild Rose120191997
Parshall119861982
Sheyenne Lk120091995

Horned Grebe Population Trend in Other States

alaskaminnesotamontanasouth-dakotawashingtonwisconsinwyoming

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