Friday 24 January 2014

[cobirds] Published summary of the stub-tailed wren split

Hi, all.

David Dowell raises some good questions:

> My online reading suggests that at the time of the Winter-Pacific 
> Wren split, no evidence of hybridization had been found, even 
> though the birds shared breeding grounds. Is there more recent 
> evidence of hybridization? Or should we invoke the "absence of 
> evidence is not evidence of absence" argument? 

Here's a nice summary and exploration of these issues, courtesy of Paul Hess in Birding magazine:


Note that Hess's summary was published *prior* to the split. The focus at that time was on genetics, gene flow (practically none, to answer one of David's questions), and vocalizations. As to morphological differences, Hess says:

"In the sampled birds, no statistically significant morphometric differences appeared in wing, tail, or
tarsus length, or in bill length and width. Aspects of plumage pattern and color were not analyzed, but pacificus is recognized as more richly colored than hiemalis."

It's remarkable just how much more we know now than just a few years ago ("pacificus is recognized as more richly colored than hiemalis.")

Ted Floyd
Lafayette, Boulder County, Colorado

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