Recently I read an article published by the Audubon Society regarding bird migration that left me wide-eyed and amazed.
I was curious about migration, especially the hummingbirds. I have a friendly running competition with a friend in Redmond. What follows our greetings is an inquiry as to hummingbird sightings. He usually wins and I am convinced it is because his location is warmer than mine.
|Anna's Hummingbird in Winter|
After reading the Audubon article I learned what an incredible, wonderous journey migration is. At summer's end, birds eat excessive amounts of food for two weeks to store enough fat for migration. They gorge themselves on high-energy berries and fruits loaded with carbohydrates and lipids that are stored as fats. That is another reason why it is important to grow native plants that produce the lipid-rich berries birds need.
Ruby-throated hummingbirds are best known for packing on the grams. Most double their weight before starting on their trip. Some gain close to half that in four days.
The metabolism of the hummingbird is one of the highest of any animal on earth. They require the equivalent of over 150,000 calories every day to power their fast-moving heart and wings, which can beat 1,000 to 3,000 times per minute. That fat is burned in a steady release of energy to make a 2,000 mile journey that many Ruby-throated hummingbirds make twice a year.
All that fat on a bird's small frame must be distributed properly. To do so, many birds are able to shrink and grow their internal organs. An example is the Bar-tailed Godwit, one of the world's most intense migrators.
What about sleep? During migration, a neurological shift triggered by the changing season forces birds to adapt to nocturnal habits and sleep less. Swainson's Thrushes migrate from Central and South America to northern Canada and Alaska, enter a sleep-like state for nine seconds at a time. They keep one half of their brain awake to avoid predators or mid-air collisions while the other half rests.
There is still an unanswered question for me--Where do hummingbirds nest? I go on a quest every summer looking, but have yet to find one.
According to the International Dark-Sky Association, April 15-May 18 is the key spring migration dates for Central Oregon. Turn your outside lights off if possible. Light pollution can cause birds to become disoriented resulting in collisions with buildings.