Bald Eagles at Oldfield

by | Jan 7, 2021 | Nature, Outfitters Center | 0 comments

LEANNA MCMILLAN, Staff Naturalist You may have seen a few bald eagles soaring above Oldfield lately, and perhaps you have seen one carrying a stick or flying around with a potential mate. January is the middle of nesting season for Bald Eagles in South Carolina. Male and female eagles build their nest together. Both eagles will bring sticks to add to the nest structure and arrange them within the nest. The nest-building activity is part of their pair bonding. The average Bald Eagle nest is 4 to 5 feet in diameter and 2 to 4 feet deep. Each year the adult pair will add 1-2 feet of new material to the nest. The largest recorded bald eagle nest, located in St. Petersburg, Florida, was 9.5 feet in diameter, 20 feet deep, and weighed almost 3 tons. Bald Eagles nest in trees usually choosing the tallest living tree (mostly pines) with accessible branches. The nest is built high in the tree below the crown supported by large forked branches near the trunk. Eagles have nest site fidelity and will use a productive nest year after year adding new material to it each year. A pair of eagles may use a nest until the nest itself becomes so large that the tree can no longer support it. In such a case, the pair might build a nest in the same territory, nearby the previous nest. Some bald eagles will have a second nest in their territory. They may use one nest for a few years and then move to the second nest for some time. Here at Oldfield, we have a Bald Eagle nest near hole #7 on the golf course high up in a pine tree. We hope the nest is active this year! There have been a few reports of activity. An eagle is mature and ready to breed at about 4 to 5 years of age. For bald eagles, the com- plete white head and tail are signs of sexual maturity. Eagles engage in dramatic courtship displays that involve swooping flight, aerial stick exchanges, and cartwheeling. These beha- viors are all part of courtship and pair bonding. Many of these behaviors also test the streng- th and agility of the potential mate. Eagles engage in significant courtship and pair-bonding behavior. Once a pair has had breeding success, the pair will likely remain together for many years. However, if a mate dies or does not return to the nesting site for the breeding season, studies show that the surviving eagle generally will find a new mate very quickly. The re- maining mate will likely use the existing nest with a new mate because of the eagles’ strong nest-site fidelity. Bald Eagles lay one to three eggs per clutch and produce one brood per year. After it is laid, the egg must be constantly kept warm, or incubated, and protected from predators. Both males and females share incubation responsibilities but the female typically spends more time on the nest than the male. Incubation for bald eagles is about 35 days. Bald eagles fledge at about 10-14 weeks. Before their first flight, nestlings will flap their wings in the nest or while jumping to an adjacent branch in a behavior known as branching. Young Bald Eagles can appear larger in their first year because of longer flight feathers which aid the fledgling as they are learning to fly. After the first molt, the wing feathers will be the same size as an adult’s. Be sure to keep an eye out for Bald Eagles flying over Oldfield!