BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Brown-crested Flycatcher

TyrannidaeAerial insectivoresMyiarchus tyrannulus

Brown-crested Flycatcher has surged: up 165% on the route-weighted index since 1969.

+165%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 →
119RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
57Years 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 Brown-crested Flycatcher

The Brown-crested Flycatcher (Myiarchus tyrannulus) 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 119 Breeding Bird Survey routes across 6 states, most concentrated in the Sonoran and Mojave Deserts.
Family
Tyrannidae · Aerial insectivores

Notable Brown-crested 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 →

long arc increasecomputed 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 →

Brown-crested Flycatcher has surged in surveyed states: up 165% on the route-weighted index since 1969.

Brown-crested Flycatcher Population Forecast

If the recent trend holds, Brown-crested Flycatcher is projected to rise about 36% by 2029 — from 0.17 in 2024 to a central estimate of 0.23 (95% range 0.17–0.28). A 5-year backtest shows a typical error of ±20.7%, with 40% of held-out values landing inside the 95% band.

+36%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 →
0.23Projected 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 →
0.17–0.2895% 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 →
±20.7%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, Brown-crested Flycatcher is projected to rise about 36% by 2029 — from 0.17 in 2024 to a central estimate of 0.23 (95% range 0.17–0.28). A 5-year backtest shows a typical error of ±20.7%, with 40% 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 →
20250.210.160.27
20260.220.160.27
20270.220.170.27
20280.220.170.28
20290.230.170.28

Where the Brown-crested Flycatcher Is Detected

BBS routes recording Brown-crested Flycatcher, sized by most recent count.

Brown-crested Flycatcher Population Trend by State

Brown-crested 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+439%197046
Californiainsufficient datan/a5
Nevadainsufficient datan/a4
New Mexicoinsufficient datan/a2
Texas+45%196961
Utahinsufficient datan/a1

Brown-crested Flycatcher Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Brown-crested 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 →
Southern Rockies / Colorado Plateau-84%19734
Edwards Plateau+121%19775
Oaks and Prairies+891%19728
Sonoran and Mojave Deserts+203%197033
Sierra Madre Occidental+492%197118
Chihuahuan Desert+64%19868
Tamaulipan Brushlands+23%196928
Gulf Coastal Prairie17×197112

Brown-crested Flycatcher Conservation Status

Our route-weighted index shows it up about 165% since 1969. 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.