Non-stop: Hummingbirds do long-distance travel
March 10, 2016
Ruby-throated hummingbirds (Archilocus colubris) get their name from the male's shining red feathers. These tiny acrobats of the air are fairly common in America. Their habitat reaches all the way north of the great lakes deep into Canada. There, some of them spend a short, but beautiful summer.
Most stay a bit farther to the south and during the summer months in the eastern U.S., somewhere between the Mississippi River and the Atlantic coast. Starting in August, they migrate south, along - and possibly also across - the Caribbean to Central America.
It is a long trip for the tiny creatures, which on average weigh only around 0.1 oz (about 3 grams) and have a wing span of only about four inches (about ten centimeters).
Computer modeling
Theodore Zenzal and his research colleagues at the University of Southern Mississippi in Hattiesburg have calculated the flying power of ruby-throated hummingbirds using a computer model.
They have found that male hummingbirds can travel more than 1,300 miles (about 2,200 kilometers) without taking a single break. They published their findings in the journal "The Auk: Ornithological Advances" this Thursday.
However, in reality, things may look different.
The researchers tracked 2,700 hummingbirds with either radio-transponders or tiny aluminum bands at their nesting places in Alabama. Then they caught and identified some of them in southern Mexico. This allowed them to follow the traveling behavior and recreational stops of the birds.
And it appears the birds needed about 62 days to travel a distance of about 1,800 miles.
Take the coast or cross the Caribbean
It remains unclear, though, whether the birds travelled along the coast or whether some of them - probably older birds - took a route across the ocean. This could be as long as 600 miles (1,000 kilometers). Those birds, which the researchers found took breaks along the coast, usually stayed in their resting places for one to four days.
What is clear is that older the birds left their northern quarters earlier than those who were just one year old. And the older ones arrived at their travel-destination earlier and generally in better physical shape than the younger ones.
"The most interesting was some birds even managed to gain weight during the journey," Zenzal told the German news agency, dpa. "But they were still able to fly well."
fs/jw (dpa)