BirdAnalyst
Species · BCR 35 · BBS 2025 Release · 1966–2024

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 →
50Routes 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 →
57YearsYears 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.

Forecast

If the recent trend holds, Cassin's Sparrow in Chihuahuan Desert is projected to rise about 170% by 2029 — from 5.3 in 2024 to a central estimate of 14 (95% range 0.00–35). A 5-year backtest shows a typical error of ±57.6%, with 100% of held-out values landing inside the 95% band.

+170%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 →
14Projected 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 →
0.00–3595% 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 →
±57.6%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 rise about 170% by 2029 — from 5.3 in 2024 to a central estimate of 14 (95% range 0.00–35). A 5-year backtest shows a typical error of ±57.6%, 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 →
2025150.0037
2026150.0036
2027150.0036
2028150.0036
2029140.0035

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 →
LangtryTEXAS1332000
RoswellNEW-MEXICO1062022
LakewoodNEW-MEXICO922021
Capitan Mtn.NEW-MEXICO852017
Coyanda DrawTEXAS662024
GirvinTEXAS582017
ComstockTEXAS552023
Ft. DavisTEXAS502023
MarathonTEXAS472023
PumpvilleTEXAS462024
AltudaTEXAS352023
Delaware CrkTEXAS342015
OzonaTEXAS272022
Red RockNEW-MEXICO262023
QueenNEW-MEXICO252021
ToyahvaleTEXAS222019
San AntonioNEW-MEXICO171977
SlaughterTEXAS162009
Devils R CynTEXAS162024
Black GapTEXAS112023
ValentineTEXAS101987
Ft. StocktonTEXAS82024
Bitter LakeNEW-MEXICO62023
Hatchet PeakNEW-MEXICO62022
LongfellowTEXAS62024

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