BirdAnalyst
Species · BCR 35 · BBS 2026 Release · 1966–2025

Black-tailed Gnatcatcher In Chihuahuan Desert

All regionsChihuahuan DesertArid-land birds

Black-tailed Gnatcatcher in Chihuahuan Desert has fallen sharply: down 58% on the route-weighted index since 1969.

-58%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 →
37Routes 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 →
56YearsYears 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 →

Black-tailed Gnatcatcher has fallen sharply in Chihuahuan Desert: down 58% on the route-weighted index since 1969.

Black-tailed Gnatcatcher In Chihuahuan Desert Population Forecast

If the recent trend holds, Black-tailed Gnatcatcher in Chihuahuan Desert is projected to rise about 44% by 2030 — from 1.4 in 2025 to a central estimate of 2.0 (95% range 0.00–4.0). A 5-year backtest shows a typical error of ±111.4%, with 100% of held-out values landing inside the 95% band.

+44%Change by 2030TrendPercent 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 →
2.0Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–4.095% 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 →
±111.4%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, Black-tailed Gnatcatcher in Chihuahuan Desert is projected to rise about 44% by 2030 — from 1.4 in 2025 to a central estimate of 2.0 (95% range 0.00–4.0). A 5-year backtest shows a typical error of ±111.4%, with 100% of held-out values landing inside the 95% band.19672030
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 →
20261.90.004.0
20272.00.004.0
20282.00.004.0
20292.00.004.0
20302.00.004.0

Routes In Chihuahuan Desert

Routes recording Black-tailed Gnatcatcher in Chihuahuan Desert.
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 →
Sierra BlancTEXAS102025
Quitman Cyn.TEXAS92009
Dove Mtn.TEXAS92006
Casa PiedraTEXAS72025
LongfellowTEXAS52019
CastolonTEXAS52025
Quitman Canyon 2TEXAS52025
Hatchet PeakNEW-MEXICO32025
Black GapTEXAS32025
LangtryTEXAS32000
Van HornTEXAS32025
PumpvilleTEXAS32025
GageNEW-MEXICO22025
Red RockNEW-MEXICO22025
MesillaNEW-MEXICO22000
ColumbusNEW-MEXICO22024
Hot SpringsTEXAS22025
GirvinTEXAS22017
Devils R CynTEXAS22024
MarfaTEXAS22022
Chisos BasinTEXAS22025
JornadaNEW-MEXICO12025
RodeoNEW-MEXICO12022
Sunshine WllNEW-MEXICO12019
ComstockTEXAS12019

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.