Our Window on Nature

Moving south for the winter isn’t a new idea - we humans were just a little slow catching on. Many creatures migrate to a more comfortable climate each year, but it’s the birds we notice most. Few people who spend time outdoors could fail to notice the disappearance of robins, or the passage of Canada geese, honking their way along avian freeways of the sky.

Bird migration has always fascinated man. Maybe it’s the thought of birds’ freedom to travel where they want - when they want. With a recreational vehicle we duplicate their movements, but the mystery of migration remains.

Like their human counterparts, birds migrate at varying speeds for varying distances. The arctic tern used to be considered the long distance champion. Not satisfied with a single summer each year, it flies all the way to Antarctica for a second summer, making a round trip of 22,000 miles. Now the record seems to be held by the Sooty Shearwater.

A banded ruddy turnstone traveled from Alaska to the Hawaiian Islands in only three-and-a-half days. An even faster trip was that of a lesser yellowlegs. On a 1,900-mile journey from Cape Cod to the West Indies the bird averaged over 300 miles per day.

Since the purpose of migration is to move to a more comfortable climate, the direction doesn’t have to be south. For birds that live on a mountain an alternative direction can simply be down. Mountain quail nest as high as 9,500 feet in the western United States. As cold weather approaches they move at least halfway down the mountain for the winter. But quail, being quail, do it differently. Single file, in small groups, they walk down the mountainside.

How do birds migrate? How do they find their way from one place to another with such accuracy? There are still more questions than answers. Some birds that migrate in daylight orient their flight to the position of the sun. This sounds simple, but consider that as the sun moves across the sky, somehow the migrating birds must make adjustments for the time of day. Have you ever seen a wristwatch on a bluebird?

Night flyers use the stars in much the same manner. They “read” the heavens like miniature astronomers to maintain their sense of direction. Experimenters study this behavior by placing birds in planetariums and switching the seasons by moving the stars around. The confused birds try to fly in the direction the stars tell them to fly. They know that stars don’t lie.

The more scientists discover about bird migration, the stranger, and more unbelievable, the whole phenomenon becomes. The tiny blackpoll warbler actually doubles in weight before beginning its migration flight - non-stop over the Atlantic for over 2,300 miles. That is comparable to a human running a four-minute mile, continuously, for about 80 hours.

Researchers find that pigeons see ultra-violet light and hear infra-sound such as that caused by the surf or by a storm thousands of miles away. Some birds can sense the difference in barometric pressure between the floor and the ceiling of a room. Some sense the earth’s magnetic field, and others have eyesight eight times better than a man.

Many of the large and spectacular water birds travel down the four major flyways on their trips north and south. Major stopping points on the southbound journey are at wildlife refuges where the general public is welcomed along with the birds. Two outstanding places to see literally millions of waterfowl along with many other feathered migrants are at Klamath Basin National Wildlife Refuges (astride the California/Oregon border with camping at nearby Lava Beds National Monument), and in the East, at Brigantine National Wildlife Refuge in coastal New Jersey.

Many other national wildlife refuges are worth a stop at this (or any other) time of year. Wildlife refuges are not only sanctuaries for birds, but for all manner of wild creatures. But for the next several months they will be the home of the original snowbirds, where you can see more large birds in one place than at any other season.