“A Year of Birding in Bloedel” is a column that runs every Friday in the Bainbridge Islander. The project is planned to continue in 52 parts through 2014 to help readers find and identify birds in the island’s garden sanctuary. Beginning with this entry on the bald eagle, each column will also be published here on the Bainbridge Conversation blog each Friday.
The author, Ted Anderson, is a retired professor of biology, having taught at McKendree University (Ill.) for 32 years and for the University of Michigan’s summer biological station for 20 years, where he frequently taught the biology of birds.
Anderson is also the author of “Biology of the Ubiquitous House Sparrow, from Genes to Populations” (2006), and “The Life of David Lack, Father of Evolutionary Ecology” (2013). Ted and his wife Carol have been members of Bloedel Reserve for seven years. They live in Kingston.
Ospreys leave their Pacific Northwest breeding ground to spend winters in South America.
Often referred to as the Fish Eagle, the Osprey (Pandion hallaetus) is the second-most widely distributed raptor species in the world, occurring on every continent except Antarctica, as well as on many oceanic islands. Its colloquial name is an apt one, as its diet is comprised of 99 percent fish, and it is nearly eagle sized. It is more slender bodied than an eagle, however, and has narrower wings that are bent at the “elbow,” giving it a distinctive silhouette when it is soaring overhead. It leaves its breeding ground in the Pacific Northwest to spend the winter in South America.
Watching an osprey fishing can lead to some truly exciting viewing. On Puget Sound a fishing osprey will often fly in large circles near the shore, then hover for a few seconds before plunging in a head-first dive toward its intended prey. Just before entering the water it shifts to a feet-first position and sometimes disappears completely beneath the surface before it re-emerges, wings flapping vigorously with a fish clutched in its talons.
What happens next may be even more exciting to watch. Often a member of that notorious tribe of kleptoparasites, the bald eagle, has also been watching the osprey fishing. The would-be bandit begins its rapid pursuit of the successful fisherman laboring to gain altitude with his catch clutched tightly in its talons.
The eagle will then dive repeatedly at the fleeing osprey, sometimes striking it from above with its own talons. More often than not the hapless Osprey will release its catch, at which point the eagle will dive to retrieve it, sometimes even catching it in the air. A dramatic example of nature “red in tooth and claw!”
While soaring, ospreys will frequently utter a high-pitched chirp call that is characteristic of the species. If you scan the sky above you when you hear this call, you will often see the circling Osprey with its white underparts and “bent” wings. Two weeks ago when I visited Bloedel I heard an osprey calling over the pond in front of the Visitor’s Center and looked up to see two ospreys soaring overhead.
Keep your ears peeled for this chirp emanating from high in the sky.
