BirdAnalyst
Species · Arizona · BBS 2025 Release · 1966–2024

Willow Flycatcher Population Trend in Arizona

All statesAerial insectivores

Willow Flycatcher in Arizona has surged: up 114% on the route-weighted index since 1998.

+114%Since 1998TrendPercent 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 →
5Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
12YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Willow Flycatcher Trends in ArizonaNotable 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 →

Willow Flycatcher has surged in Arizona: up 114% on the route-weighted index since 1998.

Willow Flycatcher Survey Routes in Arizona

Routes recording Willow Flycatcher in Arizona.
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 →
Maine520011997
Araby420212004
Laguna320212001
Dateland220121998
Blue119891989

Willow Flycatcher Population Trend in Other States

alaskaarkansascaliforniacoloradoconnecticutdelawaregeorgiaidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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