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Environmental Aspects
Wildlife
All photos courtesy of Stephanie Spears, PCC
George In flight, 2004
The Woodrow Wilson Bridge Project Team has been involved in many endeavors that promote environmental enhancement including tree reforestation, wetland restoration and creation, submerged aquatic vegetation planting, fish re-stocking and blockage removal, and of course protecting our resident Bald Eagles Haliaeetus leucocephalus . Ensuring the survival of this National emblem is a priority to the Woodrow Wilson Bridge Project.
Male, George wing stretch 2004
How Can Eagles be protected?
In order to ensure bald eagles and other wildlife will continue to thrive in their natural habitat in the Woodrow Wilson Bridge Project Area, a permanent 84-acre bald eagle sanctuary was created on March 2001on Rosalie Island in Prince George’s County, Maryland. The sanctuary is more than eight times larger than was required by the US Fish and Wildlife Service, underscoring the project’s commitment to build the new facility in an environmentally friendly manner. Just the fact that the bald eagles have decided to nest so close to the 200,000 vehicles that travel the Capital Beltway each day suggests that they may have developed a higher tolerance for human activity.
Female, Martha, perched at Rosalie Island, 2004
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Who came first?
The Project’s Environmental Team has taken a great interest in both the resident and wintering eagle activities in an effort to avoid conflict with construction activities. Well before construction started, in 1999, the Woodrow Wilson Bridge Project Environmental Team began field observations of the resident pair. Between January and June of each year, bird specialists, called ornithologists, observe the eagles twice a month from a boat in Smoot’s Cove and Oxon Cove. Between June and December, observations take place once a month. Oxon Cove is on the north side of the Beltway a likely location for birds to perch while they are fishing in the cove, which has been enhanced by the old bridge deck after it was demolished and placed into the cove to create nooks and crannies for fish to swim through. Smoot’s Cove is on the south side of the Beltway where the deep water that was mined many years ago allows for other deep-water fish to live. The birders observe the habits including fishing, mating and nesting.
Wintering bald eagles at Smoot’s Cove, 2003
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How Can You Tell the Difference?
The bird specialists can recognize the eagles by distinctive colors of their feathers, patches of colorings about their faces, beak characteristics, similar to the way that you might see differences in other like creatures such as dogs or cats. Many hours have been spent observing one pair of breeding eagles that have been part of the Woodrow Wilson Bridge Project family for several years.
Resident eagle pair, Martha is on the left, 2004
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How Long Have The Eagles Lived Near the Bridge?
In June 1998, the U.S. Fish and Wildlife Service, during a routine regional flyover, identified a Bald Eagle nest in Betty Blume Park which is a Maryland – National Capital Park and Planning (M-NCPPC) –owned park, located in Prince George’s County, Maryland south of the Beltway near the National Harbor property. This pair has affectionately come to be known as George and Martha Wilson, the first family of eagles located at the Woodrow Wilson Bridge. Eagles reach sexual maturity, mate, locate a home territory, build a nest and rear young when they are between 4-5 years of age. This is when they exhibit the distinctive white head and white tail of adults. Each year the Team has been fortunate to see this pair’s young. They also report on the number of eggs hatched and have determined the number of young fledged from the nest (first flight). They recorded the eaglets as they learn the basic skills they need to survive to adulthood and become active breeders like their parents. From the first tentative flights out of the nest to the parents teaching the young how to hunt, fly, and well, just how to be an eagle the birders have watched every move.
Resident pair, George in front, 2004
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What About the Nest?
In their first 3 years in Betty Blume Park, George and Martha successfully fledged 8 eaglets: 3 in 1998, 2 in 1999 and another 3 in 2000. They were in the nest in Betty Blume Park until a strong windstorm in Fall 2000 blew down their nest. In 2001, they built a nest farther south along the Maryland shoreline adjacent to Smoot’s Cove, closer to the Woodrow Wilson Bridge construction, and again fledged 2 eaglets. George and Martha faced further challenges when the second nest blew down after another windstorm.
Subsequently, the resident eagle pair selected a location along the southern tip of Rosalie Island, approximately 75 feet from the edge of the active work zone. Since they selected a site so close to the active work zone, they were watched as they built their nest. Eagles are known to be builders of the largest single pair nests in the world, reaching up to 12 feet in diameter and weighing up to 1,000 pounds.
One of two eaglets that fledged in 2003. Woody first flight weekend
Although the nest on Rosalie Island is not that big, the fact that eagles will use the same nest year after year, could allow George and Martha to build a significantly larger nest in the coming years. In addition to gathering fallen branches and small limbs from the shoreline and woodland interiors, the adults break large branches off live trees! The eagles would circle around the tree tops, eyeing a particular branch, start into a dive, talons lunging forward, and hit the branch with such force they would snap the branch off. The entire tree trunk would sway from the force of the strike!
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Eaglets Are on the Way…
In early April 2004 we eagerly watched as George and Martha incubated their newly laid eggs. Eagles usually lay 2 or 3 white eggs in late February to early March. In 2004 we confirmed incubation (or care of the eggs) began on March 3, 2004. Eggs began hatching out on April 8 and by April 10 the adults were seen feeding the young eaglets. Eggs may not hatch out at the same time, so there may be several days time between the first eaglet birth and any others.
Martha incubating eggs, March 2004
Incubation behavior is easily monitored. At least one of the adults is almost always in the nest. On extremely warm days, the adult can come out of the nest for up to 20 minutes without harming the young inside. At times like these, it is not unusual to observe the eagles flying down to the water surface, skimming their breast feathers along the water and flying back to the eggs, cooling the eggs with the wet feathers. Both George and Martha take turns incubating the eggs. Typically, Martha remains in the nest overnight while George roosts nearby. After George has eaten in the morning, he will take over the incubation duties for the day. Martha leaves the eggs in his care and proceeds to feed, preen (or groom), and monitor their territory by flying high above the Capital Beltway. By late afternoon, usually between 4:00 and 4:30 pm the second shift change of the day occurs, and George is once again free to eat, soar, preen, and roost and in general just be an eagle.
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How can you tell George and Martha Apart?
Adult male and female eagles look exactly the same with a body length of 30-31" long (76-79 cm) and an amazing wingspan of 6-7' 6" (1.8-2.3 m)
Incubation shift change, George on right, 2004
Because we have spent so many hours observing this resident pair, several physical differences are apparent. When the birds are in the same physical location, it’s easy to see which is the female, she’s bigger. Her body is bigger to accommodate egg laying. Martha also has something else which makes her easier to spot, her tail feathers have a reddish tint to them. When she’s soaring overhead, with sunlight streaming from above, her tail feathers look almost like red-tailed hawks! We are not certain if she got into something that left a lasting stain on those feathers, or whether it’s a result of her genes, but she’s also got some reddish feathers on the right side of her white head.
Martha in full flight, 2004
George is comparatively smaller than Martha and has a different dark brown tint on his chest and wing feathers. He’s more milk chocolate colored compared to Martha’s dark chocolate. George has also had some additional scarring on his beak, which makes it easier to tell them apart.
George at the nest, 2004
When the eggs hatch out after a 34-36 day incubation period, food will be brought back to the nest by both parents, where pieces are torn off and offered to the chicks. After several weeks, food will be left in the nest with the young responsible for feeding themselves. Fledging will occur sometime in early July. Fish comprises 80% of the eagles’ diet, however, eagles are great scavengers and will harass other birds (especially Osprey), and will often also feed on road kill, small rodents, waterfowl and eel.
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“Now That we’re out, what are we supposed to do?”
Two young eaglets in nest, 3 weeks old, 2004
And just what will the young eagles do for their first several weeks of life? Everything is new and interesting, so they will be learning and watching. They will learn eagle behavior from their parents, what foods to eat, how to catch their food, what vocalizations and expressions mean to each other and to other species of wildlife. They will learn what predators are and where they fit into the food chain. They will watch young goslings and ducklings underneath their nest tree. They will learn about fox and deer. They will learn how to fly, how to lift off and how to land, how to turn and what they can do with their talons. They will exercise their wings; they will preen their feathers. And occasionally, they will have little tiffs with their siblings in the nest.
eNature's Wildlife Audio: Bald Eagle
George and Martha will tempt them to leave the nest and begin flight training by bringing food back near the nest, but not right to the nest.
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Get out! Cried mom and dad
Even though they will receive the best of care from their parents, the first year of these new eagles lives are full of danger. Around mid fall, George and Martha will drive their offspring from the area. Where these juveniles fly to and what they do is something we don’t know. None of the eagles are tagged or radio collared.
George with newly hatched eaglet at 3 weeks old, 2004
We know that only 10% of eagles survive to adulthood, most dying from starvation. We can identify wintering birds and guess their approximate age, even before they develop the distinctive white head and tail feathers marking maturity. Differences in the chest and breast feathers provide easy identification features. We can identify adult females, which can weigh up to 12 pounds, even when young, based on their size.
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Oh, What a Life!
George and Martha’s offspring may migrate south in the winter or they may remain in the Mid-Atlantic Region. When they reach sexual maturity, the female will select a nesting area and a mate. The females control Bald Eagle terrority. Consequently, if something should happen to the male and she remains in her breeding years, she may select another mate. Eagle pairs will stop breeding between 10 and 12 years of age and then relinquish their territory to a younger mated pair. The breeding cycle will then start all over.
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Endangered and Threatened, Who Me?
Martha at the nest, 2004
Because of the endangered/threatened status of eagles, the project, in compliance with federal regulations consulted with the U. S. Fish and Wildlife Service to determine how best to protect these birds while simultaneously constructing a new bridge. In April 2000, the project produced a listing of reasonable and prudent minimization measures to the resident eagles when they are at the nest, as part of a formal technical document called an Environmental Assessment. The regulatory agency (United States Fish and Wildlife Service or USFWS) then concurred with a formal document called a Biological Opinion, each in accordance with the Endangered Species Act. These documents are updated as new information evolves.
George in flight, 2004
The policies and recommendations are strictly adhered to and have resulted in the re-alignment of a major construction haul road on the Project in Maryland, restricted areas around the nest, time of year restrictions for certain activities in locations around the bald eagle use area, and purchase of an 84 acre now being used for a Bald Eagle sanctuary on the north side of the Beltway, in Maryland.
George, 2004
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References:
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