BirdAnalyst
Species · BCR 36 · BBS 2025 Release · 1966–2024

Cassin's Sparrow In Tamaulipan Brushlands

All regionsTamaulipan BrushlandsGrassland birds

Cassin's Sparrow in Tamaulipan Brushlands has fallen sharply: down 54% on the route-weighted index since 1969.

-54%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 →
27Routes 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 Tamaulipan Brushlands: down 54% on the route-weighted index since 1969.

Cassin's Sparrow In Tamaulipan Brushlands Population Forecast

If the recent trend holds, Cassin's Sparrow in Tamaulipan Brushlands is projected to fall about 100% by 2029 — from 6.4 in 2024 to a central estimate of 0.00 (95% range 0.00–34). A 5-year backtest shows a typical error of ±185.9%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–3495% 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 →
±185.9%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 Tamaulipan Brushlands is projected to fall about 100% by 2029 — from 6.4 in 2024 to a central estimate of 0.00 (95% range 0.00–34). A 5-year backtest shows a typical error of ±185.9%, 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 →
20250.000.0034
20260.000.0034
20270.000.0034
20280.000.0034
20290.000.0034

Routes In Tamaulipan Brushlands

Routes recording Cassin's Sparrow in Tamaulipan Brushlands.
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 →
CatarinaTEXAS592010
El IndioTEXAS442007
EncinalTEXAS282010
Millett 2TEXAS262024
MillettTEXAS182012
El SauzTEXAS162023
Pedro CreekTEXAS142010
George WestTEXAS132024
Catarina 2TEXAS132017
HondoTEXAS112024
ZapataTEXAS101987
GuerraTEXAS92023
Mirando CityTEXAS82024
DilleyTEXAS72024
RandadoTEXAS62024
KingsvilleTEXAS42024
Encinal 2TEXAS42022
RachalTEXAS32023
Catarina 3TEXAS32023
San YgnacioTEXAS21985
RaymondvilleTEXAS22024
Cavasara Cr.TEXAS22023
Agua NuevaTEXAS12023
La PryorTEXAS12010
ProgresoTEXAS12006

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