BirdAnalyst
Species · BBS 2026 Release · 1966–2025

Thick-billed Longspur Population Analysis

CalcariidaeGrassland birdsRhynchophanes mccownii

Thick-billed Longspur has surged: up 16× on the route-weighted index since 1969.

16×Since 1969TrendPercent 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 →
95RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Thick-billed Longspur

The Thick-billed Longspur (Rhynchophanes mccownii) is a North American member of the Longspurs & Snow Buntings (Calcariidae). In this analysis it is grouped with the grassland birds.

Size
5.5–7 in long (14–18 cm) — a small ground songbird (typical for the family)
Habitat
Open grasslands, prairie, pasture and hayfields.
Diet
Seeds and insects gathered from grasses and the ground.
Range
Recorded on 95 Breeding Bird Survey routes across 5 states, most concentrated in the Badlands and Prairies.
Family
Calcariidae · Grassland birds

Notable Thick-billed Longspur TrendsNotable 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 Thick-billed Longspur. See the full index history below.

Thick-billed Longspur Population Forecast

If the recent trend holds, Thick-billed Longspur is projected to fall about 21% by 2030 — from 0.29 in 2025 to a central estimate of 0.23 (95% range 0.14–0.32). A 5-year backtest shows a typical error of ±35.8%, with 20% of held-out values landing inside the 95% band.

-21%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 →
0.23Projected 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 →
0.14–0.3295% 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 →
±35.8%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, Thick-billed Longspur is projected to fall about 21% by 2030 — from 0.29 in 2025 to a central estimate of 0.23 (95% range 0.14–0.32). A 5-year backtest shows a typical error of ±35.8%, with 20% of held-out values landing inside the 95% band.19672030
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 →
20260.210.120.30
20270.220.130.31
20280.220.130.31
20290.220.130.31
20300.230.140.32

Where the Thick-billed Longspur Is Detected

BBS routes recording Thick-billed Longspur, sized by most recent count.

Thick-billed Longspur Population Trend by State

Thick-billed Longspur population trend by state.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Colorado+41%197213
Montana+290%197036
Nebraska-62%19934
North Dakota-82%19713
Wyoming+125%197039

Thick-billed Longspur Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Thick-billed Longspur population trend by Bird Conservation Region.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Northern Rockies-30%197022
Prairie Potholes+422%197216
Southern Rockies / Colorado Plateau+74%19803
Badlands and Prairies33×196934
Shortgrass Prairie+219%197020

Thick-billed Longspur Conservation Status

Our route-weighted index shows it up about 1512% since 1969. Grassland birds are North America's steepest-declining group, down roughly 50% since 1970 as prairie and pasture were lost.

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14. Trend is a route-weighted relative-abundance index, not an absolute population.