Researchers came up with a new family tree for hummingbirds, describing the bird's migration from Europe, Asia, and North America before they settled at South America some 22 million years ago.
"Our study provides a much clearer picture regarding how and when hummingbirds came to be distributed where they are today," UC Berkeley associate professor of integrative biology and lead author Jimmy McGuire said in a University press release.
The researchers collected DNA data from 451 hummingbirds representing 284 species. They also gathered DNA samples from the bird's closest relatives and then compared their mitochondrial and nuclear genes. These data were used to construct a family tree, and they found out that the ancestors of the modern hummingbirds appeared 42 million years ago after splitting with the swifts and treeswifts. The split may have happened in Europe or Asia where 28-34 million years old fossils depicting humming-bird like creatures were found.
After the split, the hummingbirds traveled to South America through a land bridge connecting the Bering Strait and Alaska. Once they reached South America, they evolved into new species which will be later known as nine groups including hermits, topazes, mangoes, brilliants, mountain gems, bees, emeralds, coquettes, and the single-species group Patagona (the Giant Hummingbird, Patagonagigas). Again, 12 million years ago, the ancestors of the bee and mountain gem hummingbirds went to North America and started a co-evolution with the local flora. The other groups of hummingbirds traveled to North America, as well. Five million years ago, the hummingbirds also reached the Caribbean.
Analysis shows that the diversity of the hummingbirds allows them to continuing evolving until today. Despite the fact that they only need tiny insects and nectar to survive, there are some places that are home to more than 25 species of hummingbirds.
This study was published in the April 4 issue of Current Biology.
