Doug Leier posted on February 16, 2011 10:21 :: 1104 Views
The recovery of the bald eagle is one of the most visible conservation recovery success stories for our nation.
While the plight of whooping cranes and California condors is well documented and well known, these birds have struggled to gain ground and are still rooted on the endangered species list.
The bald eagle, on the other hand, has recovered to the point where an observation no longer results in a phone call to Game and Fish to report a sighting.
Bald eagles were not even protected until Congress passed the Bald Eagle Protection Act in 1940. Still, the continental population continued to spiral downward and in 1978 the bald eagle was listed as an endangered species. At that time North Dakota did not have a single documented bald eagle nest.
It wasn’t until the mid-2000s that the number of eagles nesting in North Dakota started to increase noticeably. To date, North Dakota Game and Fish Department biologists have now logged 103 individual nest sites, some of which are no longer in use because the trees have fallen or the eagles abandoned the sites.
Today, bald eagles are nesting in just about every region in the state except for the badlands, and nests exist in 29 of 53 North Dakota counties.
In the past few years Game and Fish biologists have seen some nests around the state that make you think, “Why there?”
Several nests are situated in a single tree or shelterbelt surrounded by cropland.
Believe it or not, one eagle pair even built a nest in a small, undisturbed draw smack in the middle of an active coal mine in western North Dakota, only to abandon it. A great horned owl pair soon took claim of it. The eagles returned the following year and successfully raised three young.
Bald eagles are opportunistic feeders. They like fish, and are known near and far as fish thieves. If they find a dead one or can steal it from another bald eagle, mammal or bird that rightfully caught, it they’ll gladly seize the opportunity.
During breeding season bald eagles are more likely to catch live prey, such as muskrats, amphibians, coots and other water birds like ducks, herons and gulls. Outside the breeding season, they’re often satisfied with carrion, such as road kill deer and pheasants.
Bald eagles mate for life, but a replacement will be sought if a mate dies. Sometime during February they’ll stake claim to a new territory, or defend last year’s site. They defend their roughly 250-500-acre territory by perching conspicuously, vocalizing and chasing intruders away if necessary. They will either build a new nest, or add a few fresh sticks and bedding material to one used a previous year.
It’s not uncommon to find eagle mates building two nests and picking their favorite for the nesting attempt that year. During March females lay 1-3 eggs intermittently over several days, but incubation begins immediately after arrival of the first egg. By about 35 days the first chick hatched will have a head start on growth.
This first-hatched wants and gets everything – most of the food and attention from adults, and prime seating in the nest. Because of this, at times the younger sibling, especially if there are three, may starve or even be killed by older siblings.
A young eagle grows quickly and is full grown when it takes its first wobbly flight from the nest 10-12 weeks after hatching, typically in July.
The sight of an eagle gives most of us a reason to pause, and a nest draws considerable attention. Too much attention, however, can cause these big beautiful national symbols to abandon their nest. So if you’re in the neighborhood, viewing from a distance with spotting scope is a good idea.
Doug Leier is a biologist with the Game & Fish Department. He can be reached by email:dleier@nd.gov
Article Source:
http://justnorth.com/Articles/tabid/105/articleType/AuthorView/authorID/220/Doug_Leier.aspx