BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Sulphur-bellied Flycatcher

TyrannidaeAerial insectivoresMyiodynastes luteiventris

Sulphur-bellied Flycatcher has no long-term trend on record.

n/aSince n/aTrendPercent 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 →
6RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
44Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Sulphur-bellied Flycatcher

The Sulphur-bellied Flycatcher (Myiodynastes luteiventris) is a North American member of the Tyrant Flycatchers (Tyrannidae). In this analysis it is grouped with the aerial insectivores.

Size
4.5–9 in long (12–23 cm) — a small to medium flycatcher (typical for the family)
Habitat
Open airspace over fields, water and towns; nests in cavities, earthen banks or on structures.
Diet
Flying insects caught on the wing.
Range
Recorded on 6 Breeding Bird Survey routes across 1 state, most concentrated in the Sierra Madre Occidental.
Family
Tyrannidae · Aerial insectivores

Notable Sulphur-bellied Flycatcher TrendsNotable 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. See the full index history below.

Sulphur-bellied Flycatcher Population Forecast

If the recent trend holds, Sulphur-bellied Flycatcher is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.00). A 5-year backtest shows a typical error of ±48.6%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.00–0.0095% 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 →
±48.6%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, Sulphur-bellied Flycatcher is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.00). A 5-year backtest shows a typical error of ±48.6%, with 100% of held-out values landing inside the 95% band.19692029
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 →
20250.000.000.00
20260.000.000.00
20270.000.000.00
20280.000.000.00
20290.000.000.00

Where the Sulphur-bellied Flycatcher Is Detected

BBS routes recording Sulphur-bellied Flycatcher, sized by most recent count.

Sulphur-bellied Flycatcher Population Trend by State

Sulphur-bellied Flycatcher population trend by state.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Arizona+4%19756

Sulphur-bellied Flycatcher Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Sulphur-bellied Flycatcher population trend by Bird Conservation Region.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Sierra Madre Occidental-31%19756

Sulphur-bellied Flycatcher Conservation Status

Aerial insectivores have fallen sharply across the continent, a decline widely linked to dwindling insect prey.

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.