Bald eagles, the national symbol of the United States since 1782, were in the recent past on the endangered species list. Now they are just on the threatened fist and the number has been increasing, but if temperatures rise as global warming predicts, what are the chances of the bald eagles returning to the endangered list?
Global warming has begun to threaten many migratory birds including the bald eagle. The birds are affected because the time of the seasons change, the food sources are different, some of the habitat is destroyed and the increase of temperature throws off the entire migration system. The total planetary temperature has increased one degree Fahrenheit during the last century because of wastes humans put into the air. Gases such as water vapor, carbon dioxide and methane are the "greenhouse’ gases. Whenever greenhouse gases are burned, they stay in the atmosphere for more than a century, causing a hole in the protective ozone layer and increasing the temperature on earth. Scientists say the migratory birds are already being affected by the increase in temperature, which causes-the seasons to change forcing birds to change their natural habits.
"The eagles are used to coming back to the same place and will become confused if it is changed," Suzie MacVean a member of the Region 2 Game and Fish department said. She thinks the change will make the eagles fly for longer periods of time searching for their home. The time of the season for bald eagles is important because they need to prepare for the long migration journey. They will have to adapt to the temperature increase and move to an area with a different environment. This will cause a great amount of strain on the eagles because they spend 94 percent of their time perched in trees and the other 4 percent catching food and the other 2 percent flying. If they have to move, they could starve or not have enough energy to escape their predator. To adapt to early season change, eagles will not have time to gather enough food by the time they need to leave. They usually double their body weight in order to make it to the destination. Bald eagles have been reportedly seen in the migratory destinations three weeks ahead of schedule
Bald eagles have a certain pattern in which they travel when they migrate and the two crucial factors to the travel are food availability and weather. Bald eagles may travel hundreds of miles without stopping. When they reach a stopping point, the global warming consequences could have already destroyed the chances of continuing the journey. Global warming consequences include the increase of diseases in rodents and fish which are a bald eagle’s main source of food, the water in the wetland destroying the nesting sites and the bald eagle getting to the destination.
Some coastal sites, such as the Chesapeake Bay, are important refueling stops for eagles. An increase in temperature could alter the hydrology that maintains the wetlands, making it unbalanced. Wetlands have a large biological diversity and are habitats for breeding ground for many migratory birds including the bald eagle. The bald eagle migrates from Alaska, Utah, Montana and other areas around the United States to the southern states such as Arizona. The stops along the wetlands are crucial for the bald eagle to continue the flight. The wetlands are nesting sites and also refueling points. The increase in temperature will be hard on the reproduction of the birds and also the existence of the eggs.
"Surely the nests would be flooded if the water level rises," MacVean said. The wetlands are the main breeding sites for most migratory birds," she said. The breeding process for the bald eagles is very critical and can easily be disrupted, leading to unborn eaglets. The breeding season for bald eagles varies with latitude and temperature. The winter breeding occurs in the south and the spring breeding in the north. If the seasons are altered by global warming, reproduction will also change. Bald eagles court for one to three months and then mate for life. Every year they will come back to the same nest which is high up in the trees built out of sticks, soil and weeds. The nest is built primarily by the female with the help of the male and will be about six feet wide the first year. Each following year the nest will be added to so that it could weigh up to two tons. The eagles will have two or three eggs per year and it is rare for both to survive. Both eagles feed the young. The competition for the food causes only one eagle to survive. An eagle’s wing span can reach 7 feet wide, and the eagle will protect the young from the harsh weather by wrapping the wings around the baby to shield it from the wind. Generally, eagles make the nest near water and wetlands. If the water continues to rise, the eagles will not have a nest to which to return. They will spend the time rebuilding the nest and not reproduce. Their life span is about 30 years and they will reach maturity and start reproducing at age five.
To ensure the reproduction of the bald eagles and the insurance that they will not only be seen on the dollar bills, we need to start taking better care of the environment. Bald eagles are affected by the products that we use and the greenhouse gases that we put into the environment. If we can cut down on those and take the bus or car pool, eagles may have a better chance of survival.
Many other migratory birds will be affected by climate change. In areas such as The Great Salt Lake, Delaware Bay, Coppename River and The Arctic many birds migrate south to areas in South America for breeding. Theses areas are affected mostly by climate change because they are in wetlands. The birds that migrate in this pattern are the American Avocets, Great White Pelicans, Pied Avocets, mallards, and Red Knots. Birds that breed in the short Arctic Summer will be largely affected by the consequences of global warming and climate change because the season is so short.
"It is hard to tell what the effects of global warming would be, but it would change a things for birds that migrate," MacVean said.