Chances are most of us won’t see a beautiful Green Heron making her winter home in our backyard. But if you happen to live along the shores and waterways that make up Hampton Roads, you may get lucky. Herons, along with a variety of grebes, ducks, rails, owls, and hawks make Back Bay National Wildlife Refuge their winter home. Back Bay is managed by the U.S. Fish and Wildlife Service specifically for the protection of wildlife and wildlife habitat.

There are always birds migrating somewhere on Earth at any given moment, day or night; spring, summer, winter or fall. Migration is one of nature’s greatest mysteries. Every year birds, mammals, fish, butterflies and insects move to climates where temperatures are more hospitable and food is more abundant, to set up new homes and breed or raise their young. What initiates migratory behavior varies and is not completely understood. Migration is thought to be triggered by a combination of changes in day length, lower temperatures, changes in food supplies, and genetic predisposition.

Here in the United States, the northern winters with cold temperatures and little food make life hard for most birds. Changes in day length cause glands in the birds’ bodies to produce hormones that in turn produce physical changes that prepare them for the flight south. As the days grow shorter, fat accumulates under the skin, and that fat will provide the energy needed for the coming days when the bird will be flying more than they’ll be eating.

There has been a long-standing dispute over how migratory birds manage to navigate for thousands of miles in sunlight, darkness and bad weather. Along with two colleagues, Princeton biologist Martin Wikelski concluded that birds rely on a combination of cues – sun and magnetic field – to guide migration. During daylight they are guided on a path that is determined primarily by the sun. To maintain their heading throughout the night, they sense the Earth’s magnetic field, just like a pilot uses a compass at night or in bad weather.

Flying in V-Formation has long been thought to provide lift for the trailing birds, thus saving valuable energy. However, recent studies suggest that most geese, for example, do not fly close enough together to get any lift from the bird ahead of it. Therefore, the reason for the V-formation is still a mystery

Not all birds fly when they migrate. When the snows arrive, the Blue Grouse leave—on foot— from the foothills of the Rocky Mountains where they summer, and walk to the bitterly cold wind-driven high country in search of evergreen trees that will provide both food and shelter. That’s a migration to a harsher climate! Some birds are short-distance migrants and migrate only as far as they need to find food such as insects, seeds and berries. Penguins migrate long distances by swimming!

Whatever the reason or season, the cycle of migration gives residents of Hampton Roads the opportunity to see a wide variety of birds in their own backyard.