Speaker 1: Welcome to Brainstuff, a production of iHeartRadio. Hey brain Stuff,
Speaker 1: Lauren Vohlbaum. Here, if you're a fledgling nation selecting a
Speaker 1: national bird, you could do a lot worse than the
Speaker 1: bald eagle. It's got the stately profile and steely eyed gaze,
Speaker 1: the dramatic contrast coloring, and huge wingspan, which is all
Speaker 1: part of why members of Congress chose the bald eagle
Speaker 1: to represent the United States in seventeen eighty nine. For
Speaker 1: the article this episode is based on How Stuffworks, spoke
Speaker 1: with Scott Cordon, wildlife curator at the Center for Wildlife
Speaker 1: Education and the lamar Q Bald Junior Raptor Center at
Speaker 1: Georgia Southern University. Cordon is an expert falconer and manages
Speaker 1: the center's najerie, which includes two bald eagles. First off,
Speaker 1: to be clear, these eagles don't have the bald moniker
Speaker 1: because their heads look hairless, but rather because they're white.
Speaker 1: Their name comes from the Middle English word bald b alde,
Speaker 1: meaning white, but bald eagles don't develop those striking white
Speaker 1: head and tail feathers until they're mature, somewhere between the
Speaker 1: ages of four and five years old. Immature Bald eagles
Speaker 1: are mostly dark brown in color, with mottled brown and
Speaker 1: white wings. They also don't fully develop the bright golden
Speaker 1: yellow coloration on their beaks and feet until they're mature.
Speaker 1: When they reach full size, bald eagles are big, with
Speaker 1: the female eagles growing a bit larger than males. Overall,
Speaker 1: they can weigh around nine to fourteen pounds that's about
Speaker 1: four to six and a half kilos, with a wingspan
Speaker 1: of around five and a half to seven feet or
Speaker 1: about one point six two one point two meters. Only
Speaker 1: a few other North American birds, like the golden eagle
Speaker 1: and the California condor, are as large or larger. Bald
Speaker 1: eagles are in the sea eagle family, meaning they live
Speaker 1: near rivers and coasts and hunt mostly fish and white fowl,
Speaker 1: but they're considered opportunistic carnivores, which means that they usually
Speaker 1: eat whatever is available, including other small game like rabbits, squirrels,
Speaker 1: or rodents, plus deadfish that have washed up on shore,
Speaker 1: or even stolen prey from other birds such as osprey's.
Speaker 1: The scientific name for this type of food snatching behavior
Speaker 1: is klepto parasitism, but it's most common among the immature birds.
Speaker 1: Once mature, bald eagles can be formidable hunters. When a
Speaker 1: bald eagle swoops down to catch its prey, it uses
Speaker 1: its razor sharp talons to snatch the unlucky animal it's
Speaker 1: decided to make a meal out of. They'll roam a
Speaker 1: pretty wide hunting territory about twenty five miles across some
Speaker 1: forty kilometers. But for all that, your average bald eagle
Speaker 1: can easily live off of a couple of adult rats
Speaker 1: per day. Corton said, most birds don't eat every day
Speaker 1: because they'll catch something that's large enough to sustain them
Speaker 1: for a couple of days. Instead, they might feed off
Speaker 1: of something large and fill their a part of their
Speaker 1: digestive system where they temporarily store food that can sustain
Speaker 1: them for two or three days, sometimes even longer. A
Speaker 1: Bald eagles are the only sea eagles endemic to North America,
Speaker 1: and they really have the territory covered. The bald eagles
Speaker 1: range stretches from southern Alaska to northern Mexico and from
Speaker 1: coast to coast. Due to their distinctive plumage, they are
Speaker 1: almost impossible to mistake with other birds, even other large eagles.
Speaker 1: When you see that white head soaring above the trees,
Speaker 1: it's a bald eagle for sure. These birds can be
Speaker 1: very social under the right circumstances. When food is plentiful
Speaker 1: and it's not nesting season, a few to a few
Speaker 1: hundred may roost together and have been observed engaging in
Speaker 1: play behavior even as adults. They also mat for life,
Speaker 1: though if one of a pair dies, the surviving birds
Speaker 1: sometimes finds a new mate and they take nesting seriously.
Speaker 1: Mates built nests called aries together, which takes around one
Speaker 1: to three months. They also trade parental duties, with both
Speaker 1: birds incubating the eggs for the five weeks or so
Speaker 1: that it takes for them to hatch, because it takes
Speaker 1: the hatchlings ten to twelve weeks to grow to the
Speaker 1: point that they fledge, that is, take their first flight.
Speaker 1: Eagles only lay one clutch or a group of eggs
Speaker 1: per year. Cordon said. If their eggs or their young
Speaker 1: are destroyed early enough in the season, they will lay
Speaker 1: another clutch to try to reproduce again. In fact, that's
Speaker 1: part of how they got the bald eagle population back up.
Speaker 1: They would remove eagle eggs from the nest early in
Speaker 1: the season and the adult eagle would lay another set
Speaker 1: of eggs. It's called a double clutch. Due to these efforts,
Speaker 1: the bald eagle was removed from the federal endangered species
Speaker 1: list in two thousand and seven and is off every
Speaker 1: state endangered species list too, though it's still protected by
Speaker 1: several laws to prevent the population from dipping again. But
Speaker 1: back to those nests. A bald eagles have the largest
Speaker 1: nest of any bird species in North America. Their average
Speaker 1: nest size is up to five feet across and four
Speaker 1: feet deep that's about one point five by one point
Speaker 1: two meters. The biggest arion record was built by pair
Speaker 1: bald eagles in Saint Petersburg, Florida. It measured twenty feet
Speaker 1: by nine feet that's about six by three meters, and
Speaker 1: weighed two tons. A Cordon explained eagles only live in
Speaker 1: their nest during the mating season, incubation, and while they're
Speaker 1: raising the fledglings. Once they learn to fly and everyone
Speaker 1: is out, they don't live in the nest. The birds
Speaker 1: will return to the same nest year after year if possible,
Speaker 1: but will leave if the tree's built in can't sustain it.
Speaker 1: They're also pretty smart. A Courton said, they tend to
Speaker 1: never forget anything, and they hold grudges. If you're training
Speaker 1: an eagle and you make a mistake, that can either
Speaker 1: ruin the training you've done or set you back several months.
Speaker 1: But it's important to note that the bald eagle wasn't
Speaker 1: the only bird in the running for a national symbol.
Speaker 1: A founding father, Benjamin Franklin and favored the turkey as
Speaker 1: the national bird, calling it more respectable and with all
Speaker 1: a true original native of America. Part of Franklin's beef
Speaker 1: was that the bald eagle is a scavenger. Corton said,
Speaker 1: of all the birds of prey other than the vultures,
Speaker 1: bald eagles will most readily go to a dead animal
Speaker 1: on the side of the road, where other birds of
Speaker 1: prey will only carry in if they're starving. Nevertheless, the
Speaker 1: bald eagle was chosen as a symbol of strength, courage,
Speaker 1: and freedom, and despite Franklin's comments, the bald eagle is
Speaker 1: indigenous only to North America. Today's episode is based on
Speaker 1: the article Bald Eagle, size, diet and History is a
Speaker 1: National Icon on HowStuffWorks dot com, written by Patty Rasmusen
Speaker 1: Brain Stuff is production of by Heart Radio in partnership
Speaker 1: with HowStuffWorks dot Com and is produced by Tyler Klang.
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