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

Thick-billed Longspur Population Trend in North Dakota

All statesGeneralists

Thick-billed Longspur in North Dakota has collapsed: down 82% on the route-weighted index since 1971.

-82%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 →
3Routes 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 →
21YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Thick-billed Longspur 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 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 →

Thick-billed Longspur has collapsed in North Dakota: down 82% on the route-weighted index since 1971.

Thick-billed Longspur Population Forecast in North Dakota

If the recent trend holds, Thick-billed Longspur in North Dakota is projected to fall about 100% by 2002 — from 0.07 in 1997 to a central estimate of 0.00 (95% range 0.00–0.13). A 5-year backtest shows a typical error of ±86.1%, with 100% of held-out values landing inside the 95% band.

-100%Change by 2002TrendPercent 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 →
0.00Projected 2002 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.1395% 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 →
±86.1%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, Thick-billed Longspur in North Dakota is projected to fall about 100% by 2002 — from 0.07 in 1997 to a central estimate of 0.00 (95% range 0.00–0.13). A 5-year backtest shows a typical error of ±86.1%, with 100% of held-out values landing inside the 95% band.19672002
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 →
19980.000.000.13
19990.000.000.13
20000.000.000.13
20010.000.000.13
20020.000.000.13

Thick-billed Longspur Survey Routes in North Dakota

Routes recording Thick-billed Longspur 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 →
Gorham419861986
Bowman319971967
Golva119941994

Thick-billed Longspur Population Trend in Other States

coloradomontananebraskawyoming

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