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Purple Finches: Male or Female?



CarolinaBirders . . .

The thread on sexing Purple Finches (PUFI) at the feeder has been interesting.

As usual, Donna Bailey (see below) is right on with her supposition 
that a "brown" PUFI with a pink wash might be an older female rather 
than a young male. Sometimes brown PUFI also have a gold rump or 
wash; I haven't looked hard at my data on this phenomenon, but I have 
a gut feeling that these are more likely to be young males.

It's difficult to get an accurate sample of sex ratios in PUFI 
without banding them; I'm fortunate to have that privilege, and have 
found here at Hilton Pond that red (actually, I prefer "raspberry") 
After-Second-Year male PUFI make up about 28% of the winter 
population, while about 72% of them are brown, i.e., old females, 
young females, or young males. If we make a flying leap of faith and 
assume the M:F ratio among PUFI is roughly 1:1, we might conclude 
that each of these three age/sex classes makes up about a third of 
the brown birds.

There's a longer discussion of this topic on my new website for 
Hilton Pond Center for Piedmont Natural History at 
http://www.hiltonpond.org. (You KNEW I'd get a plug in somewhere, 
didn't you?) I've posted a paper I wrote in 1994 for North American 
Bird Bander about banding PUFI and House Finches at Hilton Pond; it's 
in the section on "Technical Publications" and includes some photos 
that didn't appear in the original article. I hope this section 
proves useful to someone. :-)

Now I guess I'll have to stay up all night trying to figure out if 
gold-rumped PUFI really are young males . . . . .


Happy Birding!

BILL

***********


>While my memory grows creakier with each passing day, I do seem to remember
>reading somewhere that older female Purple Finches could develop a pink wash
>across the breast, much as adult female Hooded Warblers sometimes have an
>almost complete "hood" and adult female Wilson's Warblers sometimes have a
>"black cap" nearly as extensive as the males.  Still, the young male Purple
>Finches should show pink across the breast and at least a pink flush in the
>face, while the older females would have no pink in the face.
>
>But, yes, Janine, in general, the sex ratio at my feeders seems to run
>pretty close to 1:1.  Usually, there is one more male than females and I
>don't think that is a "bias of the eye".  I have an easier time picking out
>female Purple Finches that male Purple Finches because the female's white is
>so bright and "clean" amongst the buffier House Finches.  As a matter of
>fact, last Sunday around here when the weather was nasty and I watched the
>feeder all day, eventualy tallying twenty Purple Finches in view at one
>time, the crowd was mostly male - there were 12 or 13 males to 7 or 8 females.


**********

BILL HILTON JR., "The Piedmont Naturalist"
Hilton Pond Center for Piedmont Natural History
1432 DeVinney Road
York, South Carolina 29745
USA

e-mail: <hilton@hiltonpond.org>

Voice: (803) 684-5852

eFax: (503) 218-0845

Operation RubyThroat Website:  <http://www.rubythroat.org>

Hilton Pond Website:  <http://www.hiltonpond.org>

"Never trust a person too lazy to get up for sunrise or too busy to 
watch the sunset."

						BHjr.

**********