Jan 9, 2010

Bald Eagles Making a Comeback

Lee McNeely, president of the Northern Kentucky Bird Club, was pleasantly surprised this past spring at the number of American Bald Eagles he spotted on the Ohio River.  One day, on an 8-mile stretch of the Ohio between Belleview and Petersburg in Boone County, he spied 7 Bald Eagles.  “That was very unusual,” said Lee.  “Usually on a good day I’ll see one, maybe two Bald Eagles.”  The sightings though are reassuring.  The Bald Eagle is finally making a comeback in Kentucky and the lower 48. 

 

“Until the 1980’s, the previous recorded nest in Kentucky was in the early 1950’s,” said Lee.  “We went a full 35 years without a single eagle nest in the state.”  The Bald Eagle, like so many other birds, had fallen victim to the effects of DDT, a now banned insecticide in the U.S. 

 

DDT, for a period of time, was a seemingly effective insecticide. It quickly killed the mosquitoes that spread malaria and the lice that carried typhus, and is credited with saving millions of lives.  Eventually though many insects developed a resistance to DDT and produced offspring that were also resistant.  DDT was also highly toxic to the fish in our waterways.  A recipe for disaster was brewing.

 

A “persistent insecticide,” the molecules in DDT stay together as a poison for a long time before breaking down into smaller, less toxic substances.  It washed deep down into the soils, our streams, and lakes.   DDT became entrenched in the food chain.  And because it does not break down easily, DDT builds up in fatty tissues where it persists for long periods of time.  It takes an animal 8 years to metabolize one-half of the DDT it consumes – more than a lifetime for many species of birds and mammals.  Birds, like the Bald Eagle and Brown Pelican, ingested DDT after eating contaminated fish.  The DDT caused their eggshells to be thin and brittle, so brittle that eggs were broken on the nest as parents sat on them during incubation.  Eagle numbers plummeted to only hundreds of nesting birds in the contiguous U.S.

 

DDT was banned in 1972.  “Eagles have been slowly re-establishing, especially in Western Kentucky,” said Lee.  “There are also a couple of nesting pairs in the Cincinnati area, one in Brown County, Ohio and another along the Great Miami River.”  According to Kentucky Fish and Wildlife, we now have a healthy population of 48 nesting pairs of eagles in the state, with another 100 to 300 over-wintering.  Having been taken off the Federally Endangered Species List, things are looking up for the Bald Eagle.  “They have recovered well and will probably continue to do so,” said Lee.

 

The United States adopted the Bald Eagle as its national emblem in 1782.  At that time there were at least 100,000 nesting eagles in the U.S.  They were at their lowest levels, about 800 nesting eagles, in 1962 when Rachel Carson raised awareness with her landmark book Silent Spring.  Now, with their numbers steadily increasing and DDT long since banned, we have approximately 20,000 nesting eagles.

  

Most would agree that the Bald Eagle is a regal bird and an appropriate national emblem, though some would beg to differ.  “Suffer me, kind reader, to say how much I grieve that it should have been selected as the Emblem of my Country,” said John James Audubon.  “He is a bird of bad moral character; he does not get his living honestly,” complained Benjamin Franklin.  Fortunately, Thomas Jefferson and John Adams disagreed with Franklin, and with the help of Philadelphia resident William Barton, the Bald Eagle was chosen as our national emblem.

 

A true American, the Bald Eagle is the only eagle unique to North America, with a range from northern Mexico to northern Alaska and Canada.  “They’re always found close to water,” said Lee.  Fish is their staple food but they’ll also eat waterfowl, turtles, rabbits, snakes and carrion.  Like other birds of prey, females are larger than males and can weigh up to 14-pounds with an 8-foot wingspan.

 

Bald Eagles mate for life and can live more than 30 years in the wild.  Their nests are an architectural marvel, which they typically enlarge yearly.  These stick nests can reach 12-feet across and weigh more than a ton.  No other bird in the world builds such a large nest.

 

Females lay one to three eggs per year, which hatch in about 35 days.  Eaglets are flying within 3 months and are no longer dependant on their parents at 4 months.  They are sexually mature and acquire their majestic looking white head and tail feathers when they are about 4 to 5 years old.

 

American Bald Eagles are more than a national emblem.  With their near extinction and successful recovery, they represent the worst and best their human counterparts can achieve.

 

Contact Gayle at her website for nest boxes at www.woodlandhabitat.com or gaylepille@yahoo.com

 

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