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

Black-headed Grosbeak Population Trend in North Dakota

All statesGeneralists

Black-headed Grosbeak in North Dakota has surged: up 352% on the route-weighted index since 1972.

+352%Since 1972TrendPercent 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 →
22Routes 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 →
48YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Black-headed Grosbeak 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 →

long arc increasecomputed 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 →

Black-headed Grosbeak has surged in North Dakota: up 352% on the route-weighted index since 1972.

Black-headed Grosbeak Population Forecast in North Dakota

If the recent trend holds, Black-headed Grosbeak in North Dakota is projected to rise about 22% by 2029 — from 0.22 in 2024 to a central estimate of 0.27 (95% range 0.03–0.51). A 5-year backtest shows a typical error of ±69.2%, with 100% of held-out values landing inside the 95% band.

+22%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 →
0.27Projected 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 →
0.03–0.5195% 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 →
±69.2%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, Black-headed Grosbeak in North Dakota is projected to rise about 22% by 2029 — from 0.22 in 2024 to a central estimate of 0.27 (95% range 0.03–0.51). A 5-year backtest shows a typical error of ±69.2%, with 100% of held-out values landing inside the 95% band.19702029
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 →
20250.260.020.50
20260.260.030.50
20270.270.030.50
20280.270.030.51
20290.270.030.51

Black-headed Grosbeak Survey Routes in North Dakota

Routes recording Black-headed Grosbeak 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 →
Tobacco420191979
Ft Yates320041970
Douglas Crk320241982
Bentley220011989
Solen220242005
Carson119891989
Regan120181972
Dickinson120222017
Dunn Center120161986
Carpio119931980
Stanley120231980
Lark119711971
Bowman120152005
Zap120241973
Gorham120031993
Roosevelt Pk120161982
Cedar Creek120191991
Golva120221989
Glen Ullin119971989
Powers Lake119801980
Parshall120061989
Braddock120142009

Black-headed Grosbeak Population Trend in Other States

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