Exploring Nature: Marvelous M
igration
Birds really impress me when it comes to migration.
For example, this month will see bar-tailed godwits, a type of large sandpiper, fly nonstop from Alaska to New Zealand, a continuous flight of more than 7,000 miles.
One individual bird was tracked by satellite and was seen to bypass New Zealand and fly on to Tasmania, an island south of Australia. That bird had been flying non-stop for 11 days and had covered more than 8,000 miles.
This long-distance flying requires a lot of fuel and godwits fatten up before leaving Alaska. They will double their usual weight and burn fat as they fly.
They can even absorb some of their own internal organs for fuel and then re-grow them after reaching the places where they over-winter.
Black swifts fly south in the fall from their grounds in western North America. They feed by catching insects in the air and just keep on flying, sometimes for several weeks before finally reaching western South America.
These sturdy swifts stay airborne for 99% of the time, day and night, sleeping on the wing. They can fly and sleep at the same time by shutting down just parts of their brain.
The champion migrant is probably the arctic tern. This bird spends the summer in the Arctic and spends winter along the edge of the pack ice in Antarctica. That requires a 50,000-mile round-trip each year.
Young birds usually travel on their own and keep on track by navigating by the sun, the stars and the earth’s magnetic field, reaching their wintering grounds strictly by instinct.
By comparison, I can easily get lost if I don’t have a map or some GPS device to keep me on the right route.
Birds are really quite amazing.
