Aye lads
This could be beaten to death, and without banding, is insolvable, though their may be something in the literature about it. WCSP have been exceptionally well studied.




The thing is this. We think of pugets as being early arrivals and later departers. But are they? They are year long residents in my county, though often the breed in different locations (malls and parking lots as well as clear cuts) than they winter in (brushy open country). They have a fairly long longitidunal breeding range, and virtually all birds move. Birds from breeding areas are gone early, almost as soon as young are fully fledged.?




So, the question is: How far do they go. I just saw hundreds of Lutescent OCWAs in s. Baja CA, hundreds of miles s of their breeding range, yet some hardly move at all during winter. The Baja birds must have split as soon as the young were raised.?




I guess my point is this: If you visit the breeding areas of puget WCSP in the Cascades, I'll bet you they are virtually all gone. I bet if you go to the Alderwood Mall, near my house, they are nearly all gone. Which are the ones at Mike's Marymoor? Which would you call dispersants and which would you call migrants, since both sets probably winter there?




I don't know that there is an answer.




It is not as simple as with sage breeding sparrows, which clump up after breeding and then wander around in large flocks before moving a large distance to the south, alas.




Cheer
s

SteveM


-----Original Message-----
From: Wayne Weber <contopus at telus.net>
To: TWEETERS <tweeters at u.washington.edu>
Cc: MICHAEL HOBBS <birdmarymoor at verizon.net>; STEVE MLODINOW <sgmlod at aol.com>
Sent: Thu, Aug 27, 2009 9:52 am
Subject: RE: [Tweeters] Migration versus post-breeding dispersal






















Tweeters,



?



I?m glad that my message from a couple of days ago has
generated some discussion. There seems to be some agreement that ?migration?
should not be applied uncritically to all kinds of bird movement, which is the
point I was trying to make in the first place.



?



I would agree with Steve that a songbird in late summer that has
moved 60 or 100 miles south should be considered to be ?migrating?
rather than ?dispersing?.



?



However, the case of the White-crowned Sparrows in Marymoor
Park, raised by Michael Hobbs, is interesting. I?m surprised to learn
that White-crowns do not breed in the park, which seems to have suitable
habitat (hedgerows or shrubbery next to open fields). I am sure that
White-crowns breed within 2 or 3 miles of the park. (Around Vancouver, they
breed in almost every shopping center with clumps of shrubs or trees, if not in
residential areas per se.)



?



However, if White-crowns show up in Marymoor in late August,
these would have to be dispersing rather than migrating birds. ?Pugetensis?
White-crowns are short-distance migrants, with birds20breeding in Washington
travelling usually no farther than California, and at least a few of them
wintering locally (along with ?gambelii? White-crowns from farther
north). Furthermore, White-crowns don?t even start migrating until well
into September. Pugetensis arrives early in the spring (late March and April),
and leaves later in the fall than many other species. So, if White-crowns are
showing up in late August at Marymoor, it would have to be a result of
post-breeding dispersal.? One of the things that characterizes migration is
that each species has its own migration schedule, and that even closely related
species may have quite different migration schedules (e.g. Hermit versus
Swainson?s Thrushes).



?



Migration may be hard to distinguish from post-breeding
dispersal?? as I and others have noted, there is likely no clear
line between the two?but I do think it?s worth trying to
distinguish them.



?



Wayne C. Weber



Delta, BC



contopus at telus.net



??



?



?






From: tweeters-bounces at mailman2.u.washington.edu
[mailto:tweeters-bounces at mailman2.u.washington.edu] On Behalf Of Steven
Mlodinow

Sent: August-26-09 1:58 PM

To: birdmarymoor at verizon.net; Tweeters at u.washington.edu

Subject: Re: [Tweeters] dispersal






?






Hello Michael (and others)









?









A BH Grosbeak that has started its southbound migration to
wherever and has made its first 60 mile jump=2
0(or 100, etc) would be a migrant.
A WC Sparrow that has just shifted a couple miles from where it was raised
would not really be considered a migrant. I am not sure where a real
ornithologist would draw the line. Now, your WC Sparrows could in theory be
from?100 miles away, as pugetensis is migratory, and I guess that would be
a migrant. So, local movement vs long distance. Directional, vs nearest decent
habitat. I guess those would be part of the distinguishing features.









?









Best Wishes









Steve Mlodinow









Everett WA