I got to wondering about all these female Pine Grosbeaks being reported
and whether they might be a combination of mature females and immatures,
so went looking for info and found this:
"Immature male usually is indistinguishable from immature or adult
female until the second year when it molts and grows new reddish
feathers. Some young males have some red or orange feathers in the body
plumage, which females apparently lack. Females average duller than
males (especially on the crown and rump) and have a lighter russet tinge
to the head or lighter olive tinge to the breast than males. The color
of the head and body is often golden orange or reddish bronze in males,
in contrast to golden yellow of the female, and the chin is often
buffier or more brown-gray than in the female."
So there you are! Anybody who has a chance to study some of these
non-adult-male birds and can report how easy these distinctions are to
see greatly appreciated!