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

Grasshopper Sparrow In Tamaulipan Brushlands

All regionsTamaulipan BrushlandsGrassland birds

Grasshopper Sparrow in Tamaulipan Brushlands has collapsed: down 81% on the route-weighted index since 1970.

-81%Since 1970TrendPercent 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 →
19Routes 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 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 →

Grasshopper Sparrow has collapsed in Tamaulipan Brushlands: down 81% on the route-weighted index since 1970.

Forecast

If the recent trend holds, Grasshopper Sparrow in Tamaulipan Brushlands is projected to rise about 367% by 2029 — from 0.08 in 2024 to a central estimate of 0.39 (95% range 0.00–1.7). A 5-year backtest shows a typical error of ±345.1%, with 100% of held-out values landing inside the 95% band.

+367%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 →
0.39Projected 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 →
±345.1%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, Grasshopper Sparrow in Tamaulipan Brushlands is projected to rise about 367% by 2029 — from 0.08 in 2024 to a central estimate of 0.39 (95% range 0.00–1.7). A 5-year backtest shows a typical error of ±345.1%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20250.420.001.7
20260.410.001.7
20270.410.001.7
20280.400.001.7
20290.390.001.7

Routes In Tamaulipan Brushlands

Routes recording Grasshopper 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 →
El IndioTEXAS281972
ProgresoTEXAS52005
KingsvilleTEXAS22011
CatarinaTEXAS22007
GuerraTEXAS21992
SejitaTEXAS22021
MillettTEXAS22012
RachalTEXAS12015
Agua NuevaTEXAS12015
Mirando CityTEXAS11970
EncinalTEXAS11995
George WestTEXAS12019
La PryorTEXAS12004
HondoTEXAS12023
RaymondvilleTEXAS11994
El SauzTEXAS12023
Encinal 2TEXAS12024
Millett 2TEXAS12015
Cavasara Cr.TEXAS12011

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