BirdAnalyst
Species · BCR 33 · BBS 2025 Release · 1966–2024

Willow Flycatcher In Sonoran and Mojave Deserts

All regionsSonoran and Mojave DesertsAerial insectivores

Willow Flycatcher in Sonoran and Mojave Deserts has held roughly steady: down 9% on the route-weighted index since 1973.

-9%Since 1973TrendPercent 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 →
8Routes 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 →
22YearsYears 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 Willow Flycatcher in Sonoran and Mojave Deserts. See the full index history below.

Forecast

If the recent trend holds, Willow Flycatcher in Sonoran and Mojave Deserts is projected to fall about 41% by 2026 — from 0.18 in 2021 to a central estimate of 0.10 (95% range 0.00–0.26). A 5-year backtest shows a typical error of ±152.9%, with 100% of held-out values landing inside the 95% band.

-41%Change by 2026TrendPercent 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 →
0.10Projected 2026 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.2695% 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 →
±152.9%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, Willow Flycatcher in Sonoran and Mojave Deserts is projected to fall about 41% by 2026 — from 0.18 in 2021 to a central estimate of 0.10 (95% range 0.00–0.26). A 5-year backtest shows a typical error of ±152.9%, with 100% of held-out values landing inside the 95% band.19702026
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 →
20220.100.000.26
20230.100.000.26
20240.100.000.26
20250.100.000.26
20260.100.000.26

Routes In Sonoran and Mojave Deserts

Routes recording Willow Flycatcher in Sonoran and Mojave Deserts.
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 →
ArabyARIZONA42021
LagunaARIZONA32021
DatelandARIZONA22012
OnyxCALIFORNIA11997
Lucerne ValCALIFORNIA11997
Imperial DamCALIFORNIA12006
PearblossomCALIFORNIA11971
Kelso ValleyCALIFORNIA12018

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