By Cheryl Conley, TWRC Wildlife Center
Without the benefit of Google maps or Waze, they travel thousands of miles every year and know exactly where they’re going. Who are we talking about? Migratory birds, of course. About 40% of the total number of birds in the world migrate. Bar-headed geese are the highest flying and can reach heights of 5.5 miles above sea level, the altitude needed to clear the Himalayas in India. The Arctic tern travels the farthest—around 50,000 miles/year.
Why do millions of birds risk their lives to fly to different locations each spring and fall? Simply stated, it’s for survival. Food availability is the number one reason but migration is a risky business. Billions of birds are killed along their journey. Harsh weather conditions is one reason but urban sprawl tops the list. Up to one billion die every year due to window collisions and about 7 million die from strikes with radio and TV towers.
But how do they know where they’re going? Researchers believe that birds have a mineral substance above their beaks called magnetite. It helps them determine the earth’s magnetic field so they can find true north. They also use sunrise and sunset to distinguish between east and west. Night flyers will use the moon and constellations to help guide them. Birds also learn to recognize landmarks like mountains and rivers. And how do they know when to go? Birds can “feel” when it’s time to go. Outside temperatures and shorter daylight hours trigger a hormone in birds. For a couple of weeks prior to leaving, they eat more than usual and often times will double in weight. The extra weight will help them survive their long journey.
Spring is in the air and many species of migratory birds are headed our way to spend the summer. They’ll be busy building nests and raising their young before heading out in the fall.
TWRC Wildlife Center has a great opportunity for all those interested in feeding and caring for baby birds. It’s a wonderful experience! For more information, go to www.twrcwildlifecenter.org and click on “VOLUNTEER.” There you’ll find the Baby Bird Program listed.