Hi Tweets,

Finally some time to get into the mail and play!

Don Cecile writes:

> For the past few years I have been noticing (at least locally) that the
> audubon race of Yellow-rumped Warbler has been arriving at least one week
> prior to the spring arrival of the myrtle race. I wonder if others have
> noticed a similar trend or whether this is unusual?

That's consistent with Vancouver BC: 4-10 days seems about the range between
the northbound arrival of the two races.

> As far as wintering birds are concerned, thus far we do not have any records
> of overwintering audubon and myrtles rarely overwinter in large numbers.
> For this reason it is quite easy to detect the first spring arrivals. I
> would imagine this may be a bit more of a challenge for those of you that
> live farther south where more significant numbers of myrtles overwinter.

Not necessarily, Don; the first migrants show up as conspicuous
alternate-plumaged singing males within silent, drabber basic-plumaged
wintering populations. Average arrival of March 23 northbound, September 14
southbound here, BTW.

> Tentatively then, the bit of data that I have locally also suggests that the
> audubon race outnumbers the myrtle race at the beginning of the northbound
> migration but later the myrtle race takes over and in total number of
> migrants that pass through here, probably outnumbers the audubon.

> Anyone have any comments?

As far as I know, Don, while he was here Al Jaramillo was the only one in
Vancouver BC to pay any real attention to this kind of question. You might
want to query him. My own observations over the years are much less
detailed, suggesting only that Myrtles and Audubons are about equally
represented through most of the migration.

M

Michael Price
Vancouver BC Canada
mprice at mindlink.net