The first comprehensive map of hummingbirds' 22-million-year-old family tree has just been reconstructed. Published in the latest issue of Current Biology, the family tree was based on careful analysis of 284 of the world’s 338 known hummingbird species.
The new evolutionary tree shows that ancestral hummingbirds split from swifts about 42 million years ago, probably in what are now Europe and Asia. Swifts, as their name implies, can be speedy fliers, but they tend to be heftier than hummingbirds.
Treeswifts, such as this whiskered treeswift, are related to hummingbirds. As for other swifts, the whiskered treeswift is larger than most hummingbirds. Its natural habitats are tropical, moist lowland forests in Thailand, Singapore, the Philippines and a handful of other countries.
About 22 million years ago, the ancestral species of all modern hummingbirds had made its way to South America. That’s where hummingbird evolution really took off, especially in the Andes Mountains. To this day, about 140 different hummingbird species live there.
Most birds produce lift when they flap their wings down, but hummingbirds are such fast flappers that they produce lift on the upstroke too, by inverting their wings. The motions are so fast that they make a humming sound.
Jim McGuire of the University of California at Berkeley, who worked on the recent study, said, "Hummingbirds have essentially been reinventing themselves throughout their 22-million-year history."
Their unique coloration differs widely per species. In many species, the coloring does not come from pigments in the feathers, but instead results from prism-like cells within the top layers of the feathers. When light hits these cells, similar to when light shines on a crystal, the light splits into wavelengths that reflect to the observer in varying degrees of intensity.
This green-crowned brilliant hummingbird shows off its flashy colors, captured in full sunlight.
Humans aren't the only ones who admire hummingbird colors. During mating season, males will often puff out their chests to display their gorgeous feathers. Males will also move their heads from side to side, causing the feathers to flash in the light.
Daniel Osorio, a professor of neuroscience at the University of Sussex, told Discovery News that "birds can probably see more colors than us," potentially making the display all the more impressive for female hummingbirds. This Costa's hummingbird could put on quite a show. Males will also do a sort of in-flight dance in front of females, to display their strength and control.
We don't think of hummingbirds as being strong, but McGuire and his colleagues point out that these birds have adapted to all kinds of challenging environments, including low-oxygen regions and high-altitude mountain peaks.
Hummingbirds in flight have the highest metabolism of all animals.
Male bee hummingbirds are the smallest of all known birds. Their name comes from the fact that they can often be mistaken for bees, given their diminutive size, colorful bodies and buzz-like hum. This species colonized North America about 5 million years ago, according to the new study.
Deborah Matthews Lott of the Florida Museum of Natural History told Discovery News that bee hummingbirds have moved into some surprising places. Case in point: They are prevalent at Guantanamo Bay, Cuba, best known worldwide for its controversial detainment and interrogation facility of the U.S. military.
Many hummingbirds co-evolved with flowers, explaining why each is often such a perfect fit to the other. Both flowers and hummingbirds benefit from the arrangement. The birds feed from nectar, while the flowers are pollinated by hummingbirds. Here, a male coppery-headed emerald hummingbird in Costa Rica was captured feeding on flowers near a 330-foot-high waterfall.
From a distance, this individual might look like a hummingbird. In fact, it's a hummingbird clearwing moth. These large moths -- possessing a wingspan of up to 2.2 inches -- have spindle-shaped bodies that are largely covered by a thick coat of fur. Like hummingbirds, the wings of these moths beat extremely fast. They sport exotic colors as well.
Hummingbird nests are so tiny that most people miss seeing them in their gardens. This little nest, for example, was constructed out of tiny leaves, spider webs, bits of twigs and other materials. The precious contents inside are well protected, seeming to blend in with the landscape.
The future looks bright for birds in the family Trochilidae, which includes all hummingbirds. McGuire and his team concluded, "Our findings strongly indicate that hummingbirds remain engaged in a dynamic diversification process, filling available ecological and spatial niches across North America, South America, and the Caribbean."
In other words, hummingbirds are survivors that likely will continue to expand their range in coming decades.