Re: MacGillivray's Warbler
Jlstasz@aol.com
Thu, 24 Sep 1998 22:46:44 EDT
Hi Folks!
I would like to add to Bob Ringler's post about the "MacGillivray's" from the
banding station. There were two birds, both immatures. At the time they were
the latest ever of that Oporornis type for Maryland [it was mid-October]. In
hand study and a complete set of measurements did not rule out MacGillivray's.
This included measurements of the wing, tail, and undertail coverts. The
banders present at the station were quite familiar with Connecticut Warblers
and "typical" Mourning Warblers of all ages.
The birds were transported alive to the Banding Lab at Patuxent Wildlife
Research Center, where they were examined by many of the staff. No one was
ready to identify the birds. I would point out that the birds were so
different, I thought we were dealing with two different species.
Both are now in the National Museum....in a drawer labeled *Oporornis
philadelphia*. Both have been examined by a number of experts... Allan R.
Philips added a notation to the immature male "Aberrant plumage" and on the
immature female he added a note "philadelphia?" The immature female, although
in a drawer with Oporornis philadelphia, is still unlabeled to species.
Caution is needed with all plumages of Mourning Warbler. Read carefully how
Jon Dunne deals with adult males. He notes that birds lacking white eye-
crescents have to be Mourning Warblers, but birds with white-eye crescents can
be either Mourning or MacGillivray's. As with many identifications, a single
"field mark" is not always definitive.
Good Birding!
Jim
Jim Stasz
North Beach MD
jlstasz@aol.com