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

Olive Sparrow In Tamaulipan Brushlands

All regionsTamaulipan BrushlandsGeneralists

Olive Sparrow in Tamaulipan Brushlands has surged: up 725% on the route-weighted index since 1969.

+725%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 →
28Routes 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 increasecomputed 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 →

Olive Sparrow has surged in Tamaulipan Brushlands: up 725% on the route-weighted index since 1969.

Olive Sparrow In Tamaulipan Brushlands Population Forecast

If the recent trend holds, Olive Sparrow in Tamaulipan Brushlands is projected to fall about 22% by 2029 — from 18 in 2024 to a central estimate of 14 (95% range 8.9–18). A 5-year backtest shows a typical error of ±20.1%, with 60% of held-out values landing inside the 95% band.

-22%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 →
8.9–1895% 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 →
±20.1%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, Olive Sparrow in Tamaulipan Brushlands is projected to fall about 22% by 2029 — from 18 in 2024 to a central estimate of 14 (95% range 8.9–18). A 5-year backtest shows a typical error of ±20.1%, with 60% 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 →
2025137.918
2026138.218
2027138.418
2028138.618
2029148.918

Routes In Tamaulipan Brushlands

Routes recording Olive 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 →
EncinalTEXAS422010
George WestTEXAS362024
Millett 2TEXAS352024
SejitaTEXAS292024
KingsvilleTEXAS232024
HondoTEXAS232024
Agua NuevaTEXAS222023
RachalTEXAS182023
RandadoTEXAS162024
Mirando CityTEXAS162024
CatarinaTEXAS162010
El SauzTEXAS142023
Catarina 3TEXAS112024
RaymondvilleTEXAS102024
GuerraTEXAS92023
MillettTEXAS92012
La PryorTEXAS82017
DilleyTEXAS82024
LaredoTEXAS62021
San YgnacioTEXAS51982
Pedro CreekTEXAS42010
Cavasara Cr.TEXAS42023
Encinal 2TEXAS32024
Catarina 2TEXAS22017
ZapataTEXAS11983

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