Millie Mocker

Millie Mocker
Thanks to Millie's friend, Greg Harber, for her photo.

Monday, September 10, 2012

Migration

So many of my summer friends are flying south to spend winter in Central or South America and
then return to North America in the Spring. Although these friends are leaving, new friends
will arrive to spend winter in Alabama. My next newsletter will introduce you to these winter
migrants. Have you ever wondered why birds migrate? There are two reasons: temperature and food. No matter what the reason why they leave, it all depends on the bird’s survival. These southern habitats have readily available food sources and habitats for the birds to spend their winter “vacation.”

What triggers the need to migrate? Even though there could be plenty of food in a habitat, the birds will still migrate. The changing of length of the day from sunrise to sundown, lets birds know that it is time to travel. As the day length shortens, birds become “antsy.” They start gorging on food to build body fat for the long journey. Some birds, like Chimney Swifts” will congregate together and travel south in a large flock. Other birds migrate by themselves. Most birds migrating
through Alabama will cross the Gulf of Mexico to reach Central and South America. That’s a long journey to fly. Doppler radar, used to track storms, can also track migrating flocks of birds flying at night. You can see these nighttime migrants by looking through a telescope at the moon. You will see
these migrating birds as they cross in front of the moon.

Have you thought about birds in South America migrating north for their winter? Some birds do. No matter where birds migrate to, they always migrate back to their breeding grounds.

Which bird species do you think migrates back to North America
first? Post your answers below under comments!

No comments:

Post a Comment