Saturday, January 15, 2005

Michigan’s first Virginia’s Warbler

On the morning of 13 May 1993, an unusual bird was removed from the mist nets of the Rouge River Bird Observatory on the UM-Dearborn campus.  Initially, the bird appeared to be a strangely-plumaged Nashville Warbler (Oreothlypis [Vermivora] ruficapilla).

The bird was primarily grayish, with little or no contrast between the color of the head and that of the back and wings; the back and wings were not olive-colored like a Nashville Warbler. There was a restricted amount of yellow on the upper breast and undertail coverts with much of the breast and belly grayish, rather than the uniform yellow of a Nashville. Like a Nashville, the bird had a complete, pale gray eye ring, and a small concealed rufous crown patch. We had an unbelievable hunch about what it was, and after going through a series of photographic references and technical references, we confirmed that this bird was not a Nashville Warbler, but rather the closely related Virginia’s Warbler (Oreothlypis [Vermivora] virginiae).

This capture represented the first record of Virginia’s Warbler for Michigan. In summer, this species is normally found in the Rocky Mountain southwest. It winters mostly in mountainous regions of Mexico, and also California.

Virginia's Warbler and Julie Craves
The typical breeding habitat for Virginia’s Warbler is dense shrubs, Ponderosa pine and pinion-juniper forests at 7500 to 8000 feet elevation.
This Virginia’s Warbler had a great deal of body fat, and weighed 9.1 gr. After it was banded and photos and other measurements taken, it was released. It was not resighted.
Prior to this 1993 record, there were very few records of Virginia’s Warbler east of the Mississippi. They were:
  • 16 May 1958, Point Pelee National Park, Ontario. Male, collected.
  • 6 October 1962, banded at Island Beach State Park, Ocean Co., New Jersey.
  • 9 to 11 May 1974, photographed at Point Pelee National Park, Ontario.
  • 5 May 1975, Point Pelee National Park, Ontario.
  • 6 May 1979, Evanston, Illinois.
Since the RRBO record, there have been two others in Michigan. One 20 to 21 May 1997 in Chippewa County, and the other a bird banded 25 June 2006 in Kalamazoo County.

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