BirdAnalyst
Species · BCR 37 · BBS 2025 Release · 1966–2024

Cassin's Sparrow In Gulf Coastal Prairie

All regionsGulf Coastal PrairieGrassland birds

Cassin's Sparrow in Gulf Coastal Prairie has fallen sharply: down 67% on the route-weighted index since 1971.

-67%Since 1971TrendPercent 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 →
13Routes 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 →
36YearsYears 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 Gulf Coastal Prairie: down 67% on the route-weighted index since 1971.

Forecast

If the recent trend holds, Cassin's Sparrow in Gulf Coastal Prairie is projected to stay roughly flat through 2029, near 0.65 (95% range 0.00–1.7). A 5-year backtest shows a typical error of ±734.8%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.65Projected 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 →
0.00–1.795% 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 →
±734.8%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, Cassin's Sparrow in Gulf Coastal Prairie is projected to stay roughly flat through 2029, near 0.65 (95% range 0.00–1.7). A 5-year backtest shows a typical error of ±734.8%, 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 →
20250.640.001.7
20260.640.001.7
20270.650.001.7
20280.650.001.7
20290.650.001.7

Routes In Gulf Coastal Prairie

Routes recording Cassin's Sparrow in Gulf Coastal 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 →
KatyTEXAS112011
IndianolaTEXAS82011
San PedroTEXAS62018
BaysideTEXAS41996
Bayside 2TEXAS42001
Goliad PrairieTEXAS42015
Lag AtascosaTEXAS32013
Loyola BeachTEXAS32009
PetronilaTEXAS22014
Loyola Beach 2TEXAS12024
L. Atascosa NwrTEXAS12017
McfaddinTEXAS12013
Padre Island PaisTEXAS12015

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