Jeff Green | Sep 03, 2009
Back to HomeOutdoors in the Land O'Lakes - September 3, 2009 A Bald Eagle Familyby Lorraine Julien
It was thrilling to learn this summer that we have a Bald Eagle family on Kashwakamak Lake. The exciting part is that two youngsters have survived and have now matured to the point of leaving the nest (generally, less than half of eaglets hatched reach maturity). In the accompanying photograph, you can see one of the young birds being watched over by a parent. This photograph, along with other beautiful pictures of the eagles, was taken by Tara Elliot of Kelowna, B.C. who was visiting this summer at her uncle’s cottage.
Though there are 59 species of eagles worldwide, there are only two found exclusively in North America. One, of course, is the Bald Eagle; the other is the magnificent Golden Eagle. In Canada, the majority of these birds are found along coastal areas of British Columbia and some of the Maritime provinces. Smaller populations are found in Ontario. (Note: Much of the data and statistical information contained here was taken from the excellent Environment Canada website).
When identifying these birds, the first thing you look for is the white head, but the white head and tail feathers do not appear until the birds have reached maturity at about four years of age. Unlike most other species of birds, there is no difference in the colouring of males and females but females are usually larger. Wingspans can reach up to eight feet across. These awesome predators rely on their excellent vision to survive: eagle vision is five times as sharp as ours, enabling them to pick out prey over an area of five square kilometers from 300 metres above.
Bald Eagles generally mate for life but if a mate dies, the remaining bird will seek another mate. In the wild, they’ve been known to live up to 28 years and in captivity, as much as 36 years.
Generally, one to three eggs are laid and are incubated for about 35 days by both adults. The eaglets are fed for up to 12 weeks until their feathers have developed and they’ve learned to fly. Bald Eagles feed mostly on live fish and aquatic birds although they sometimes scavenge food from their cousin, the Osprey. They also eat smaller mammals, amphibians and reptiles. Deer carcasses are a major source of food in winter.
The hard-to-pronounce, proper name for this powerful predator is Haliaeetus leucocephalus (Haliaeetus means “sea eagle” and leucocephalus means “white head”).
Bald Eagles were once a common sight in North American skies. Beginning as far back as the 1500s, however, habitat loss and persecution seriously depleted Bald Eagle populations. By the 1700s and 1800s, the eagle population began a dramatic decline with the influx of settlers. Bald Eagles were killed for their feathers, and because the birds were considered to be vermin and a predator of farm animals.
It wasn’t until the early 1900s that conservationists brought the problem of possible extinction to the attention of American authorities. In response, the United States government intervened in 1940 and passed the Bald Eagle Act, which reduced direct killing of the birds and helped slow the population decline.
Another major factor that attributed to a huge loss of Bald Eagles was the use of DDT and other pesticides that were in use along shorelines and agricultural areas from the late 1940s to the 1970s. The toxic residue left by these pesticides affected the eagles’ ability to reproduce.
Since the 1950s, no Bald Eagles had nested on the north shore of Lake Ontario; however, by the early 1980s, Bald Eagle populations began to recover, no doubt due to the significant cutback in the use of deadly chemicals. Still, Bald Eagles face many challenges, which include ongoing problems with human-caused deaths, bad weather, poor food supply and pollution.
Today, Bald Eagles are very slowly recovering from being almost on the brink of extinction. Even as recently as 2000, in southern Ontario, only 28 eaglets were known to fledge or successfully develop to the point of leaving the nest. Of the eaglets that did survive that year, some birds were from Frontenac and Northumberland Counties.
Good news update: I’ve learned from Bird Studies Canada that southern Ontario’s Bald Eagle population has increased to the point that it has been downgraded from being on the “Endangered” list to one of “Special Concern”.
The toxic chemical sensitivity of Bald Eagles has led scientists and conservationists to identify the birds as a bio-sentinel species. This means that the health of eagles can be taken as a reliable indicator of the health of aquatic ecosystems in the Great Lakes region (similar to the canary in the coal mine scenario).
Much work still needs to be done to ensure that future generations will have the thrill of seeing this powerful bird soaring on the updrafts or diving at full speed towards the water, talons outstretched for its prey!