Airdate: Apr 26, 2000
Scientist: Doug Altshuler
Hummingbirds are antisocial, and that's just one thing that sets them apart from other birds.
The smallest bird in the world is about the size of a bumblebee. It probably won't surprise you to hear that it's a species of hummingbird, but that's not the only thing that makes hummingbirds exotic members of the bird community. I'm Jim Metzner, and this is the Pulse of the Planet, presented by DuPont.
Hummingbirds are the only birds that can do "sustained hovering" -- actually flying in place for long periods of time. Doug Altshuler is a biologist at the University of Texas in Austin.
"Hovering flight in hummingbirds is a special adaptation for their diet of flower nectar because many flowers do not provide perches for them, so they need to hover to gain access to that very energy-rich flower nectar."
All this hovering involves a lot of wing-beating -- up to eighty times a second. Right now we' re listening to the flapping wings of a ruby-throated hummingbird. This kind of flight burns up a lot of fuel, so hummingbirds consume double their weight in flower nectar every day.
"Hummingbirds can go without food for long periods of time. For example, the ruby-throated hummingbird which is common on the east coast of the United States, actually makes a migration across the Gulf of Mexico, from the Yucatan to Texas, Louisiana and Florida and this migration can take up to eighteen hours, during which time of course the hummingbird does not eat and is flying constantly."
And hummingbirds differ from many other birds in another respect -- they're decidedly antisocial.
"They spend most of their lives alone. They will meet each other at flowers and almost always fight over them. They will meet briefly during mating, when the male will court the female and very briefly mate with her. But as far as we know, nest-building, feeding the young, anything like that seems to be extremely rare in male hummingbirds."
For pictures and previews of future programs, please visit nationalgeographic.com. Pulse of the Planet is presented by DuPont, bringing you the miracles of science, with additional support provided by the National Science Foundation. I'm Jim Metzner.