On Sunday, I stopped by Carl Thornton Park in Santa Ana,
where the only highlights were two female Vermilion Flycatchers: one was a
yellow-flanked immature bird with pale brown (retained juvenile) primary
coverts (photo 1) and the other was a yellow-flanked adult with dark gray (freshly-replaced)
primary coverts (photo 2). I hadnt been aware of the yellow-flanked adult
female phenomenon until the late, great Doug Willick (actually in great health,
but reliably late and great) had just such a bird a decade ago at famed El Modena
Park in Orange that returned for consecutive winters in essentially the same dull
plumage. Ive since photographed several of these immature-female-like adults
with telltale fresh gray primary coverts, a few of which Ive included in the
link below. The yellow tends to be a little richer than that of immatures,
sometimes with a hint of salmon, but not the expected rich salmon-pink of most
adults. The only identification caveat is that some immatures molt more of their
inner primary coverts than others, thus having a mix of older brown and newer
gray coverts, and raising the possibility of being misconstrued as adults. https://photos.app.goo.gl/9KKM6vZxuVxyGbXz7

Jim Pike HB