Hi there Tweeters,

The 'crowned' sparrows have invaded California in the last week or two,
they are everywhere, including my backyard. As I sit here looking out, I see
all sorts coming to my feeder, which is nice (no White-throated Sparrow yet
though). A couple of points are worth mentioning. First of all I have all
three 'pale lored' White-crowned Sparrows coming to my backyard. These are
the Puget Sound WC Sparrow (Z.l.pugetensis), Nuttall's WCS (Z.l.nuttalli)
and the Gambel's WCS (Z.l.gambeli). I have been able to test many of the
marks given in the recent article in _Birding_ and confirmed that most of it
is right on, except perhaps call notes. The two west coast birds, Puget
Sound and Nuttall's are very similar, but when together they are easily
differentiable at least here in this part of the range of Nuttall's. As
well, Nuttall's is the local resident, so I have been able to gain a good
deal of experience with them. In Washington, and the lower mainland of BC it
should be more straightforward to identify these forms as Nuttall's will not
be present.
The other point, is that in my backyard Golden-crowns outnumber the
White-crowns and do a lot of chasing and jostling for position as they feed.
My subjective impressions are these regarding their flock dominance
behaviours: 1) Golden-crowns are dominant to White-crowns, as I have yet to
see a WCSP chase off a GCSP. 2) Golden-crowns with brighter crown markings
(lots of variability in crown markings) appear to win most of the
interactions with birds with dull crown markings. I would need to start
scoring crowns and interactions to give you a definitive answer, but this is
my subjective observation so far.
As I understand it, Sievert Rohwer at U. of Washington has done
experiments with the Harris's Sparrow in winter and found something similar.
There is good deal of variation in head and breast markings in the Harris',
but birds with more black in the winter tend to have a higher social status
than dull birds. It would be interesting to confirm that the Golden-crown,
the only other Zonotrichia that has a variable winter plumage, shows a
similar type of relationship between brightness and status within the flock.

Who says backyard birding is boring!

Good Birding,

Al 'Margaret M. Nice' Jaramillo

Alvaro Jaramillo
Half Moon Bay, CA

alvaro at quake.net
http://www.quake.net/~alvaro/index.html