The story begins with two hummingbirds sharing the same familiar name.
The Bahama woodstar is comprised of two subspecies: Calliphlox evelynae evelynae and Calliphlox evelynae lyrura. The former can be found throughout the islands of the Bahamas, particularly those in the north. The latter is seen only on the southern Inaguan islands of the Bahama Archipelago.
This month in the journal The Auk, the researchers from UCR argue that the two birds should be regarded as distinct species, which would create a kind of "everything old is new again" situation.
"The two subspecies were originally described as separate species, partly on the basis of small differences in the tail feathers between them, but were then classified in 1945 as subspecies of the Bahama woodstar," said study team member Christopher J. Clark, a UCR assistant professor of biology, in a statement. "It’s time now to call these two distinct species of hummingbirds."
Clark and his team based that conclusion upon the results of comparative analyses of the birds' sounds made during field recordings of courtship, scolding, and singing. They also compared beak and wing lengths between lyrura and evelynae and used tissue samples to figure out how much their populations' genetics diverged.
After all was said and done, the researchers determined that the adult male lyrura's tail was more strongly forked and the sound its tail feathers made during courtship much higher than that of evelynae.
Meanwhile, lyrura's scolding calls were qualitatively different from evelynae's and the birds' singing styles differed greatly (evelynae's songs were deemed "rambling" while lyrura's sounded to the team like "wet, squeaky shoes").
Finally, the DNA analysis told the UCR team that the two birds diverged genetically about 400,000 to 1 million years ago.
Read more at Discovery News
No comments:
Post a Comment