Hi Tweeters:

Dennis wrote (but I don't know when 'cause my new Real Job + commute limits
my Tweeter Time to reading one or two posts a day, big rats):

>A really obvious walk points away from any emberizine bunting (including
>our North American sparrows) except for longspurs and Snow/McKay's (or
>is it MacKay's?).

An instance in direct exception to this usual rule: one September day in the
southbound migration I was sitting on a lawned hillside S of Jericho Pk. in
Vancouver BC watching about 60--70 of what used to be called Water Pipits
just pottering around like a bunch of guys on a too-hot day looking through
the grass for someone's dropped car-keys. A few of them started messing
around in the grass at the base of a tree nearby. Suddenly, out from behind
the tree walks a smaller *pale-brown streaked* bird. My heartbeat went from
72 to 964 in a second flat: what Old-World Pipit was I looking at?
Red-throated? Pechora? As I watched this bird walking around, desperately
trying to memorize fieldmarks, I noted it was not tail-pumping. Odd. Odder
still was the little stubby bill, not quite right for a pipit. No sweat, I
thought, I've seen pipits with damaged bills before, but what the heck pipit
is this bird? I watched it walking with the other pipits for--get this--at
*least* half a minute.

And then it began to hop again and resumed its career as a Savannah Sparrow.

So I watched this some more and noticed whenever the bird was within a foot
or so of pipits, or became surrounded by a group of pipits, it would begin
to walk, though not nearly for so long as the first sighting. I noticed also
that the other Savannahs did the same thing for a few seconds under the same
circumstances.

And that's how I came to know that Savannah Sparrows can be, however
temporarily, confused with a basic-plumaged Red-throated Pipit, who'd have
thought it?

Why the mimicry? Maybe the sparrows had discovered that feeding with pipits
was easier after the larger bird had knocked down grass seeds from the
higher stems in its own foraging, and the SAVS had learned to take
advantage. Maybe Sparrows That Walk With The Pipits (a little-known
archetype) have also learned that the bigger birds will run them off if they
don't walk the same walk.

Do they migrate together? I'm not sure. I think this association was
fortuitous, but the SAVS behavior indicates it's happened before. Of course,
maybe the sparrows were walking because they were just too damned tired of
hopping ;-)

Michael Price
Vancouver BC Canada
michael_price at mindlink.bc.ca