Sunday, March 24, 2013

Bald Eagle

Bald Eagle

By 1963, courtesy of DDT and other organic pesticides, which thin egg shells, there were only 417 known nesting pairs of Bald Eagles in the lower United States!!!! 

Rachel Carson published Silent Spring in 1962, and this book turned the tide and ushered in the modern conservation movement. By 1993 the census was up to 4500 nesting pairs.
The white head and tail in this bird photographed at Frank Lake on March 22, 2013 implies the bird is mature and at least 4 years of age. 

There were at least two Bald Eagles at Frank Lake that day. likely feeding on ducks. Fish are another common prey. Bald Eagles are good foragers and in the early spring before the ice is off the rivers, I commonly see these raptors in fields, where I presume they are on the look out for small mammals. These large opportunistic raptors often take fish from Osprey. 

The five photos above were shot on March 23, 2013 in Griffith Woods behind my home. I saw the eagles from a mile away and managed to get close enough for these photos, which were taken from about a hundred meters away. I was on the northern bank of the Elbow and the birds were at the top of Spruce trees on the southern bank. The trees were about 40 or 50 meters tall. Just before the sequence above, the male tried to mate with the female but his overture was not accepted.

Over this last weekend of March 22, 23 and 24th, I saw Bald Eagles every day, including at least two at Frank Lake, one at Inglewood, and at Griffith Woods, I saw the perched pair above on the Friday, and two more on the Sunday. Clearly the Bald Eagle is thriving where I live!

Bald Eagles have the largest nest of any North American bird. Two eggs are usually laid but only one chick usually survives. These raptors live for over 30 years.                                                               


The Atlas of Breeding Birds of Alberta. Federation of Alberta Naturalists. 2007.

Baicich PJ, Harrison CJO. Nests, Eggs, and Nestlings of North American Birds. Princeton UP. 2005.

Dunne P, Sibley D, Sutton C. Hawks in Flight. Houghton Mifflin Co. Boston. 1988.

Fisher C, Acorn J. Birds of Alberta. Lone Pine Publishing. Edmonton. 1998.

Sibley David A. The Sibley Guide to Bird Life & Behavior. Alfred A Knopf, Inc. New York. 2001.

Scotter GW, Ulrich TJ, Jones EJ. Birds in the Canadian Rockies. Prairie Books. Saskatoon. 1990.

Tudge Colin. The Bird. Crown Publishers. New York. 2008.

No comments: