>On June 19, at Buck Meadows on Manashtash Ridge (about 4000 ft. elevation), I
>observed three woodpeckers which I thought, at first glance, might be
>juvenile Flickers. However, after following them around a bit, I believed
>them to be female Williamson's Sapsuckers.. These three birds were brown,
>with the back and sides heavily barred (and spotted) with black and white.
>The heads were plain brown and they all had white rump patches. The one bird
>whose underside I was able to see had a black upper breast and yellow belly.
>They were noticeably smaller than adult N. Flickers. This seemed to me early
>for juveniles, but I couldn't find information on breeding dates for
>Washington. They seemed to behave like juveniles, with lots of chattering and
>flying quite low to the ground. The only other explanation I can think of is
>that this species might, in some circumstances, be somewhat colonial.
> However, my experience in the past has been that they are pretty much
>limited to a pair in one location.
> I have been unable to find much information on juvenile Williamson's
>Sapsuckers. Does anyone have information on breeding chronology for
>Washington?
>Thanks for any information.
>Brenda Senturia
>Bbsenturia at aol.com

Brenda, the bird with the black upper breast was an adult female
Williamson's. Not only does Williamson's show a unique degree of sexual
dimorphism among the woodpeckers, but the juveniles are similarly
dimorphic, only duller than the adults. Juvenile females lack the black on
the breast and have a whitish-yellow belly but otherwise look much like
adult females. Juvenile males have a white instead of red throat, also a
faded yellow belly, but are otherwise much like adult males.

I wonder if what you saw was two juveniles accompanying an adult. I think
there's a chance they could be fledged by 19 Jun, although our two WA
juveniles are from 5 and 14 Jul. Conversely, I don't have a clue why 3
adult females would be hanging out together, not without a great show of
aggression. They aren't supposed to be colonial or social.

Woodpeckers are unusual in that the juveniles of many species show sexual
dimorphism (our two common nuthatches do the same, but very few other birds
do), and I've speculated that the adults feed and care for only the young
of their own sex after they leave the nest. As these hole-nesters have
fairly large clutches, this might be an efficient way to allocate parental
care. I don't know what the evidence is for this, as I haven't followed up
on it, but it would be a great study.

Dennis Paulson, Director phone 206-756-3798
Slater Museum of Natural History fax 206-756-3352
University of Puget Sound e-mail dpaulson at ups.edu
Tacoma, WA 98416