Saturday Science: Hummingbirds' 22 Million-Year-Old Family Tree

22 million years. I had no idea hummingbirds had been around that long. And they've been very successful at being hummingbirds.

The new, time-calibrated evolutionary tree shows that ancestral hummingbirds split from the swifts and treeswifts about 42 million years ago, probably in Eurasia. By about 22 million years ago, the ancestral species of all modern hummingbirds had made its way to South America, and that's when things really took off.

The Andes Mountains are a particular hotspot for hummingbird evolution, because diversification occurred along with the uplift of those peaks over the past 10 million years. About 140 hummingbird species live in the Andes today.

Hummingbirds are the major, if not only, pollinators for certain species of orchids, which, funny thing, also show remarkable diversity and adaptation in the Andes. Hummingbirds are, however, a New World phenomenon. Their niche as orchid pollinators in the Old World seems to be largely the province of certain species of moths. Well, where there' a niche, there's an organism, I always say.

(Not that hummingbirds pollinate only orchids, or that orchids are only pollinated by hummingbirds. But there's a strong relationship among certain species, and a lot of evidence for co-evolution.)

And a little bit of a romantic vision, courtesy of Martin Johnson Heade (who did a lot of paintings of orchids and hummingbirds, if I remember correctly):

Orchid with Two Hummingbirds, 1871