BirdAnalyst
Species · BCR 16 · BBS 2026 Release · 1966–2025

Cassin's Sparrow In Southern Rockies / Colorado Plateau

All regionsSouthern Rockies / Colorado PlateauGrassland birds

Cassin's Sparrow in Southern Rockies / Colorado Plateau has surged: up 436% on the route-weighted index since 1976.

+436%Since 1976TrendPercent 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 →
31Routes 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 →
47YearsYears 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 →

Cassin's Sparrow has surged in Southern Rockies / Colorado Plateau: up 436% on the route-weighted index since 1976.

Cassin's Sparrow In Southern Rockies / Colorado Plateau Population Forecast

If the recent trend holds, Cassin's Sparrow in Southern Rockies / Colorado Plateau is projected to rise about 79% by 2030 — from 0.82 in 2025 to a central estimate of 1.5 (95% range 0.07–2.9). A 5-year backtest shows a typical error of ±1116.5%, with 40% of held-out values landing inside the 95% band.

+79%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 →
1.5Projected 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 →
0.07–2.995% 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 →
±1116.5%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, Cassin's Sparrow in Southern Rockies / Colorado Plateau is projected to rise about 79% by 2030 — from 0.82 in 2025 to a central estimate of 1.5 (95% range 0.07–2.9). A 5-year backtest shows a typical error of ±1116.5%, with 40% of held-out values landing inside the 95% band.19712030
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 →
20261.40.002.8
20271.40.012.8
20281.40.032.8
20291.40.052.8
20301.50.072.9

Routes In Southern Rockies / Colorado Plateau

Routes recording Cassin's Sparrow in Southern Rockies / Colorado Plateau.
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 →
PasturaNEW-MEXICO1182025
Corona EastNEW-MEXICO641995
Horse MtnNEW-MEXICO122023
PecosNEW-MEXICO112017
MountainairNEW-MEXICO112024
Cerro VerdeNEW-MEXICO102019
LudlowCOLORADO52011
ValenciaNEW-MEXICO41995
Gallo ArroyoNEW-MEXICO42021
NageesiNEW-MEXICO32024
TorreonNEW-MEXICO32025
La CienegaNEW-MEXICO32022
CounselorNEW-MEXICO32019
CebollaNEW-MEXICO22006
CrownpointNEW-MEXICO21992
DulceNEW-MEXICO22018
La PlataNEW-MEXICO22010
Salt Lake 2NEW-MEXICO22024
The GapARIZONA11971
AlamosaCOLORADO12012
San LuisCOLORADO12024
AntonitoCOLORADO12004
WalsenburgCOLORADO12019
GardnerCOLORADO12024
MesitaCOLORADO12017

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.