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

Cliff Swallow In Tamaulipan Brushlands

All regionsTamaulipan BrushlandsAerial insectivores

Cliff Swallow in Tamaulipan Brushlands has collapsed: down 84% on the route-weighted index since 1969.

-84%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 →

Cliff Swallow has collapsed in Tamaulipan Brushlands: down 84% on the route-weighted index since 1969.

Forecast

If the recent trend holds, Cliff Swallow in Tamaulipan Brushlands is projected to fall about 100% by 2029 — from 8.1 in 2024 to a central estimate of 0.00 (95% range 0.00–145). A 5-year backtest shows a typical error of ±170.6%, 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 →
0.00–14595% 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 →
±170.6%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, Cliff Swallow in Tamaulipan Brushlands is projected to fall about 100% by 2029 — from 8.1 in 2024 to a central estimate of 0.00 (95% range 0.00–145). A 5-year backtest shows a typical error of ±170.6%, 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 →
20250.000.00145
20260.000.00145
20270.000.00145
20280.000.00145
20290.000.00145

Routes In Tamaulipan Brushlands

Routes recording Cliff Swallow 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 PryorTEXAS1032017
LaredoTEXAS832023
MillettTEXAS802009
El IndioTEXAS602000
Pedro CreekTEXAS482010
George WestTEXAS452024
KingsvilleTEXAS402012
HeidelbergTEXAS202024
SejitaTEXAS161997
Mirando CityTEXAS152012
Encinal 2TEXAS152024
HondoTEXAS142024
San YgnacioTEXAS131985
ZapataTEXAS121987
Agua NuevaTEXAS61985
CatarinaTEXAS61984
Catarina 3TEXAS62018
Cavasara Cr.TEXAS42013
RachalTEXAS32013
ProgresoTEXAS32010
Millett 2TEXAS32024
RaymondvilleTEXAS22008
RandadoTEXAS12014
EncinalTEXAS12006
El SauzTEXAS11994

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