BirdAnalyst
Species · BCR 35 · BBS 2026 Release · 1966–2025

Cassin's Sparrow In Chihuahuan Desert

All regionsChihuahuan DesertGrassland birds

Cassin's Sparrow in Chihuahuan Desert has fallen sharply: down 56% on the route-weighted index since 1969.

-56%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 →
51Routes 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 →
58YearsYears 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 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 →

Cassin's Sparrow has fallen sharply in Chihuahuan Desert: down 56% on the route-weighted index since 1969.

Cassin's Sparrow In Chihuahuan Desert Population Forecast

If the recent trend holds, Cassin's Sparrow in Chihuahuan Desert is projected to stay roughly flat through 2030, near 14 (95% range 0.00–35). A 5-year backtest shows a typical error of ±37.1%, with 100% of held-out values landing inside the 95% band.

-7%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 →
14Projected 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 →
0.00–3595% 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 →
±37.1%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, Cassin's Sparrow in Chihuahuan Desert is projected to stay roughly flat through 2030, near 14 (95% range 0.00–35). A 5-year backtest shows a typical error of ±37.1%, with 100% 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 →
2026150.0036
2027150.0036
2028150.0036
2029140.0035
2030140.0035

Routes In Chihuahuan Desert

Routes recording Cassin's Sparrow in Chihuahuan Desert.
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 →
Coyanda DrawTEXAS1492025
LangtryTEXAS1332000
Bitter LakeNEW-MEXICO1042025
MarathonTEXAS1022025
LakewoodNEW-MEXICO922021
Capitan Mtn.NEW-MEXICO852017
RoswellNEW-MEXICO632025
PumpvilleTEXAS412025
GirvinTEXAS372025
AltudaTEXAS352023
Delaware CrkTEXAS342015
OzonaTEXAS272022
Red RockNEW-MEXICO262023
QueenNEW-MEXICO252021
MarfaTEXAS242025
ToyahvaleTEXAS222019
San AntonioNEW-MEXICO171977
SlaughterTEXAS162009
Black GapTEXAS112023
ValentineTEXAS101987
ComstockTEXAS92025
Hatchet PeakNEW-MEXICO62022
CornudasTEXAS62018
LaborcitaNEW-MEXICO52018
EscondidaNEW-MEXICO52025

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