BirdAnalyst
Species · BCR 34 · BBS 2025 Release · 1966–2024

Black-tailed Gnatcatcher In Sierra Madre Occidental

All regionsSierra Madre OccidentalArid-land birds

Black-tailed Gnatcatcher in Sierra Madre Occidental has edged down: down 18% on the route-weighted index since 1971.

-18%Since 1971TrendPercent 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 →
16Routes 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 →
53YearsYears 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 →

No notable trend signals for Black-tailed Gnatcatcher in Sierra Madre Occidental. See the full index history below.

Forecast

If the recent trend holds, Black-tailed Gnatcatcher in Sierra Madre Occidental is projected to rise about 52% by 2029 — from 1.4 in 2024 to a central estimate of 2.1 (95% range 0.64–3.6). A 5-year backtest shows a typical error of ±258%, with 40% of held-out values landing inside the 95% band.

+52%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 →
2.1Projected 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 →
0.64–3.695% 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 →
±258%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 Sierra Madre Occidental is projected to rise about 52% by 2029 — from 1.4 in 2024 to a central estimate of 2.1 (95% range 0.64–3.6). A 5-year backtest shows a typical error of ±258%, with 40% 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 →
20252.00.573.5
20262.10.593.5
20272.10.613.6
20282.10.623.6
20292.10.643.6

Routes In Sierra Madre Occidental

Routes recording Black-tailed Gnatcatcher in Sierra Madre Occidental.
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 →
CutterARIZONA372014
Carr MtnARIZONA162024
BlueARIZONA61974
SahuaritaARIZONA62023
PomereneARIZONA52024
Bartlett ResARIZONA42024
RedingtonARIZONA42023
Aztec PeakARIZONA31977
San SimonARIZONA22023
SunizonaARIZONA21997
PortalARIZONA22021
Peña BlancaARIZONA12023
AmadoARIZONA12023
McnealARIZONA12021
Sunizona 2ARIZONA12023
DragoonARIZONA12005

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