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

Bell's Vireo In Tamaulipan Brushlands

All regionsTamaulipan BrushlandsForest birds

Bell's Vireo in Tamaulipan Brushlands has collapsed: down 76% on the route-weighted index since 1969.

-76%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 →
23Routes 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 →

Bell's Vireo has collapsed in Tamaulipan Brushlands: down 76% on the route-weighted index since 1969.

Bell's Vireo In Tamaulipan Brushlands Population Forecast

If the recent trend holds, Bell's Vireo in Tamaulipan Brushlands is projected to fall about 82% by 2029 — from 1.8 in 2024 to a central estimate of 0.31 (95% range 0.00–3.4). A 5-year backtest shows a typical error of ±153.7%, with 100% of held-out values landing inside the 95% band.

-82%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 →
0.31Projected 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 →
0.00–3.495% 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 →
±153.7%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, Bell's Vireo in Tamaulipan Brushlands is projected to fall about 82% by 2029 — from 1.8 in 2024 to a central estimate of 0.31 (95% range 0.00–3.4). A 5-year backtest shows a typical error of ±153.7%, 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 →
20250.460.003.5
20260.420.003.5
20270.380.003.4
20280.350.003.4
20290.310.003.4

Routes In Tamaulipan Brushlands

Routes recording Bell's Vireo 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 →
La PryorTEXAS142009
Millett 2TEXAS112024
El IndioTEXAS102007
CatarinaTEXAS72010
DilleyTEXAS62024
EncinalTEXAS52010
LaredoTEXAS52016
HondoTEXAS32024
Cavasara Cr.TEXAS32013
RachalTEXAS21996
Catarina 2TEXAS22013
SejitaTEXAS22021
Agua NuevaTEXAS11981
ZapataTEXAS11971
RandadoTEXAS12023
Mirando CityTEXAS12014
San YgnacioTEXAS11979
George WestTEXAS12024
GuerraTEXAS12012
Encinal 2TEXAS12018
Catarina 3TEXAS12023
MillettTEXAS12012
Pedro CreekTEXAS12010

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