Sunday, September 27, 2020

Eagle Eyes Over Marco Island

The immature bald eagle, such as seen here, is sometimes mistaken for a golden eagle. However, young bald eagles have more white mottled into their coloration overall. The golden eagle is more solid in color, and it has a beak that is more blue-black, with a nearly black tip. Eagles molt in patches, taking almost half a year to replace feathers, starting with the head and working downward. Not all feathers are replaced in a given molt. Until the bald eagle is mature, the replacement feathers are of different colors. As adults, the belly and back are dark, while the head is pure white. The distinct juvenile pattern, signaling that a bird is not ready to breed, may reduce aggression from territorial adults. As juvenile bald eagles mature, their head and tail feathers gradually turn white; simultaneously the eyes and beak gradually turn yellow. Complete transformation to maturity is achieved sometime in the fifth year. (www.baldeagleinfo.com)

The immature bald eagle, such as seen here, is sometimes mistaken for a golden eagle. However, young bald eagles have more white mottled into their coloration overall. The golden eagle is more solid in color, and it has a beak that is more blue-black, with a nearly black tip. Eagles molt in patches, taking almost half a year to replace feathers, starting with the head and working downward. Not all feathers are replaced in a given molt. Until the bald eagle is mature, the replacement feathers are of different colors. As adults, the belly and back are dark, while the head is pure white. The distinct juvenile pattern, signaling that a bird is not ready to breed, may reduce aggression from territorial adults. As juvenile bald eagles mature, their head and tail feathers gradually turn white; simultaneously the eyes and beak gradually turn yellow. Complete transformation to maturity is achieved sometime in the fifth year. (www.baldeagleinfo.com)

Conservation works and it is working in our back yards. One of the most beloved and symbolic birds in America was saved due to past and current conservation efforts. Conservation efforts that banned the use of certain chemicals, used habitat protection and regulation over development allowed the American Bald Eagle (Haliaeetus leucocephalus) to regain its glory and repopulate its native lands. Biologists, who monitor and manage the American Bald Eagle population for the past thirty to forty years, have said that this species has made an astounding comeback all over the nation, but particularly in Florida. Florida, to date, has the larges Bald Eagle population in the lower 48 states.

In 1973 monitoring began in Florida. Only eighty eight (88) active nests were found in the entire state after the initial surveys. Today, there are approximately 1, 340 active nests, 3565 adult eagles and 1,796 young in the 2009 season (This is an increase of 301 young from the 2008 season). Collier County had twenty one (21) nests last year. Marco Island is very fortunate to have two of these active nests right on the island in the midst of neighborhoods, schools and recreation.

For many years, building huge nests, typically five feet in diameter, in the native Slash Pine trees, there were two pairs of adult eagles with active nests located on the island golf course. Sometimes both of the pairs produced young but most years, just one pair produced young. One of the nests was eventually abandoned, leaving the constant, one, active pair and their nest on the golf course. This nest produces one, two and even three eaglets each year. This year, there is one eaglet. It currently perches and flaps on the edge of the nest just waiting to learn to take flight. It is common to see one or both of the adult eagles perched in nearby pines watching over their one, perfect eaglet! Golf course management, golfers and residents who enjoy the grounds behind their homes, tell of the beauty watching the eagles dive for fish and soar above.

The other eagle nest location is approximately 3 miles away from the golf course. Recently, for just two years, there has been an active nest on a large property near Tigertail Beach, called Tract K. A few years earlier, very young (and naive?) eagle pair attempted to build a nest, but were chased away by one of a Bald Eagle’s worst aggressor, a Great Horned Owl. It was very dramatic to see these big birds scrimmaging for territory.  That year, the owl won. But, last year, the eagle pair, or perhaps a new pair, returned and successfully built a large cone-shaped nest in an Australian Pine tree. Two young were produced successfully. This year, the same scenario has unfolded, and like the eaglet on the golf course, you can see two very large, all brown, eaglets perched on the rim of their nest, hopping and pumping their big wings, hoping to fly, while the parents watch from neighboring trees.

How do you tell the difference between male and female Bald Eagles? Very carefully and preferably with a high powered scope: The beak of a female eagle is deeper (distance from top to chin) than the beak of a male.

How do you tell the difference between male and female Bald Eagles? Very carefully and preferably with a high powered scope: The beak of a female eagle is deeper (distance from top to chin) than the beak of a male.

Beach walkers report sitings of these eagles fishing off of Tigertail Beach and in Collier Bay.

These eaglets will take flight soon. The adult eagles started the nesting season, tentatively last October, but more actively into late November. Taking about 35 days to incubate, both the male and female eagles will both sit on the eggs, taking turn to hunt and eat. The female will be more prominent in the nest and once the egg(s) hatch, the female is vigilant in the nest while the male will constantly hunt and provide food. Their diet is fish and lots of it. The adults shred the meat and coax the young to eat. An eaglet grows fast and can gain one pound every four to five days – at six weeks, the chicks are just about the size of their parents which can weigh between 12 and 14 pounds, have heights of 35 to 37 inches and wingspans between 79-90 inches. Once the downy feathers are shed, the first flight will take place between the tenth and thirteenth week. The eaglets will perch on the edge, flapping and even hopping, hoping to catch a breeze. Some research states that only 40% of the young survive their first flight. This time of year, wildlife and raptor rehabilitative centers get numerous calls to retrieve (large) eaglets on the ground. Many times, it is as simple as putting the eaglet back in the nest but there are times when wings, ribs or legs need healing before release of the eaglet is appropriate back to the wild. Last year, one of the Tract K eaglets was discovered in a nearby back yard – much to the surprise of the neighbor and the eaglet! Once checked out and given a clean bill of health by the Conservancy of Southwest Florida’s Wildlife Rehabilitative Center, a friendly tree trimmer used his bucket truck to place the eaglet back up in the nest!

Once the eaglet is fledged (acquire feathers necessary for flight), the fledglings will stay near the nest for six to nine weeks learning to hunt and perfect flying. The parent eagles will still feed the fledglings but not interact with them too much. Finally, the fledgling will migrate, leaving the nest site before the adult eagles. The adult Bald Eagles in Florida rarely migrate as there is no need to “follow its food.” They will not use the nest, but may perch in trees, or widen their range of hunting until the next nesting season. The immature Bald Eagles may travel far to Canada or travel a very wide range for its first few years. Not all fledglings return to their origin but some do. So, in four or five years, the mature Bald Eagles may come back to Marco Island to nest and start this cycle again…right in our own back yards.

Nancy Richie is the Environmental Specialist for the City of Marco Island and may be reached at nrichie@cityofmarcoisland.com.

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