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Species · BCR 34 · BBS 2026 Release · 1966–2025

Sulphur-bellied Flycatcher In Sierra Madre Occidental

All regionsSierra Madre OccidentalAerial insectivores

Sulphur-bellied Flycatcher in Sierra Madre Occidental has declined: down 38% on the route-weighted index since 1975.

-38%Since 1975TrendPercent 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 →
6Routes 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 →
45YearsYears 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 Sulphur-bellied Flycatcher in Sierra Madre Occidental. See the full index history below.

Sulphur-bellied Flycatcher In Sierra Madre Occidental Population Forecast

If the recent trend holds, Sulphur-bellied Flycatcher in Sierra Madre Occidental is projected to rise about 47% by 2030 — from 0.07 in 2025 to a central estimate of 0.11 (95% range 0.00–0.39). A 5-year backtest shows a typical error of ±41.5%, with 100% of held-out values landing inside the 95% band.

+47%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 →
0.11Projected 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 →
0.00–0.3995% 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 →
±41.5%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, Sulphur-bellied Flycatcher in Sierra Madre Occidental is projected to rise about 47% by 2030 — from 0.07 in 2025 to a central estimate of 0.11 (95% range 0.00–0.39). A 5-year backtest shows a typical error of ±41.5%, with 100% of held-out values landing inside the 95% band.19692030
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 →
20260.120.000.40
20270.120.000.39
20280.120.000.39
20290.110.000.39
20300.110.000.39

Routes In Sierra Madre Occidental

Routes recording Sulphur-bellied Flycatcher 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 →
PatagoniaARIZONA22022
SunizonaARIZONA21978
PortalARIZONA22025
Aztec PeakARIZONA11977
Sunizona 2ARIZONA12024
RuckerARIZONA12009

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