Eagles continue to flourish in desert - East Valley Tribune: Arizona

Eagles continue to flourish in desert

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Posted: Friday, March 14, 2008 1:49 pm | Updated: 9:13 pm, Fri Oct 7, 2011.

The sheer rock cliffs that surround Lake Pleasant Regional Park might not seem like the ideal home for a pair of bald eagles, but for the third straight year the reservoir has been a successful breeding ground for America's symbol.

View photo gallery of eagles in Arizona

On Thursday biologists with Arizona Game and Fish Department traveled to the eagle's nest site in the northeast corner of the lake to count and band the eaglets successfully hatched by one of the 48 breeding pairs of bald eagle in Arizofna.

Those in attendance for the eaglet banding first had to travel 20 minutes by boat across the lake, they then had to hike up the backside of the mountain to a rock cliff the breeding pair has chosen as their home.

"This is one of two nests in the area," said biologist Kenneth Jacobson, head of the Arizona Game and Fish Department Bald Eagle Management Program. "The eagles recently left one of the nests for their current one."

The 21-year-old adult male eagle is breeding with his third different female and the latest mate switch may have something to do with the nesting change, officials said.

This little arm of Lake Pleasant has been closed to the public for months as the eagles first prepared the nest and then laid their eggs. Now that the baby eagles have hatched, the area closure will continue to allow the parents to care for their young.

Jacobson said it is possible that another pair of eagles could nest in the abandoned site, especially with populations on the rise.

He said the state record is 42 fledglings in a season, but that record should be broken this year.

In order to record the eaglet's information, Kyle McCarty, a biologist with Game and Fish had to rappel down the side of the cliff and into the massive nest the eagles have built.

Waiting inside were several dead fish and two healthy eaglets. It's normal for a breeding pair of eagles to have two offspring. Females incubate longer and are much larger as adults, while male eagles hatch sooner so they can compete with their hungry sister.

"There is a pecking order in the nest," said James Driscoll, head of the Arizona Game and Fish Department Raptor Management Program. "There's dominance and submissiveness.

"If there is a substantial food source, then there is an excellent chance for both chicks to survive."

This year the Lake Pleasant pair hatched two male eaglets. They weighed in at roughly 2.5 kilograms a piece and were about 4-weeks-old.

"They are just a lot of skin and (downy feathers) right now," Jacobson said. "They won't build muscle for several weeks. They are using all their energy to grow feathers."

Biologists weigh and measure the animals to check their health. They band the legs with identification markers so that the birds can be tracked and studied.

Arizona eagles are very similar to raptors in more traditional settings, except for their size (they are smaller) and their nesting habits. Arizona eagles are more likely to nest on cliffs than other birds of prey. Most bald eagles nest in trees.

"All they really need is fish and water," Jacobson said. "And Arizona actually offers plenty of both."

Bald eagle populations were decimated in the 20th century but breeding efforts and the banning of DDT pesticide led to their resurgence. In 1995 the species was reclassified from Endangered to Threatened on the U.S. federal government's list of endangered species. This past summer the bald eagle was removed altogether from list. But in Arizona the animals are still listed as Threatened because the population is somewhat unique, Driscoll said.

In Arizona the birds do face some challenges. Fishing hooks and line are often found tangled around birds. Officials urge anglers to throw away their line properly instead of leaving on shorelines. On Thursday no line or hooks were discovered in the nest, just fish bones and egg shells.

Heat is also another issue for desert eagles. But adults have been known to use their impressive wingspan to shield their babies from the sun, Driscoll said. By the time the weather is getting towards triple digits the birds will be ready to fly and will make their first trip to the lake for a refreshing drink.

For months a group of dedicated nest watchers all over Arizona have been watching the breeding pairs. Their reports help biologists understand the animals and fix problems that may be hindering the birds' success.

Nest watchers will continue to spy on the nestlings for some time before allowing them to fledge the nest naturally.

Although bald eagles can be seen in Arizona year round, they are more abundant in the winter months. During this time, bald eagles from northern states migrate south to take advantage of Arizona's mild winter weather. Bald eagles often concentrate in areas with abundant food, since winter food resources can be limited. Some of the best areas to view these winter eagle concentrations are near high mountain lakes such as Upper and Lower Lake Mary near Flagstaff; Rainbow and Show Low lakes near Pinetop; and Roosevelt Lake near Globe. Watch eagles from a distance and use binoculars or spotting scopes to get a closer look.

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