BirdAnalyst
Species · BCR 18 · BBS 2025 Release · 1966–2024

Thick-billed Longspur In Shortgrass Prairie

All regionsShortgrass PrairieGeneralists

Thick-billed Longspur in Shortgrass Prairie has surged: up 209% on the route-weighted index since 1970.

+209%Since 1970TrendPercent 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 RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 →

Thick-billed Longspur has surged in Shortgrass Prairie: up 209% on the route-weighted index since 1970.

Thick-billed Longspur In Shortgrass Prairie Population Forecast

If the recent trend holds, Thick-billed Longspur in Shortgrass Prairie is projected to rise about 28% by 2029 — from 1.5 in 2024 to a central estimate of 1.9 (95% range 0.57–3.3). A 5-year backtest shows a typical error of ±77.1%, with 100% of held-out values landing inside the 95% band.

+28%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 →
1.9Projected 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 →
0.57–3.395% 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 →
±77.1%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 Shortgrass Prairie is projected to rise about 28% by 2029 — from 1.5 in 2024 to a central estimate of 1.9 (95% range 0.57–3.3). A 5-year backtest shows a typical error of ±77.1%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20251.90.483.2
20261.90.513.3
20271.90.533.3
20281.90.553.3
20291.90.573.3

Routes In Shortgrass Prairie

Routes recording Thick-billed Longspur in Shortgrass Prairie.
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 →
RockportCOLORADO752024
CheyenneWYOMING302024
NunnCOLORADO202021
GroverCOLORADO172024
AgateNEBRASKA171999
BriggsdaleCOLORADO82007
YoderWYOMING51971
Adams Co.COLORADO22016
ChugwaterWYOMING22024
Pine BluffWYOMING22009
RushCOLORADO12024
Gordon CreekCOLORADO12018
CrowleyCOLORADO11997
StonehamCOLORADO12021
LimonCOLORADO12022
EllicottCOLORADO11999
Arsenal 2COLORADO12022
KimballNEBRASKA12015
Agate 2NEBRASKA12024

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