Haliaeetus leucocephalus, more commonly referred to as Bald Eagles, are extraordinary chordates residing to the kingdom Anamalia. These Aves are large and incharge with their huge wingspan, sharp talons and unbelievable routines which they display while soaring through the sky. Over many years these birds have evolved to live in certain environments with the ability to catch their prey with ease, and reproduce to continue the population of their species.
Part of the order falconiformes, and the family Accipitridae (Seaworld parks & entertainment, “2018”), Bald Eagles are notorious for their size, behaviour, and comeback in population following being greatly affected by DDT (Wrinkler, “2002”). Additionally, they are distributed throughout North America, so many of the issues the species has faced due to pollution is very local.Bald Eagles can be found living as far north as Alaska, and as far south as Baja California and Florida (Seaworld parks & entertainment, “2018”).
Within their vast range of habitation, the birds are generally found living within 3 kilometers from an oceanic shore or body of water within forested areas. Inside of this 3 kilometer range, Bald Eagles patrol areas ranging from 1-2 square kilometers of their nest (Florida Fish and Wildlife Conservation Commission, “2017”), which is typically found atop of tall pine trees within pine forests (Seaworld parks & entertainment, “2018”). It is essential that the birds find a suitable nesting place in isolation from people, with large bodies of water close by to ensure they have an ample fish supply for food (Canadian Geographic,”2006″). Considering that Bald Eagles are able to eat fish, it is evident that there are not small birds.
The average fully grown Bald Eagle can be up to 1 metre in height and bear a 2-3 metre wingspan. Male birds range from 3.5-4 kg, while female birds are 4.5-6 kg. In order for these birds to maintain such a size, their hunting abilities need to be immaculate. As a result, the birds have developed eyesight which is about 4 to 8 times better than that of humans.
This allows the birds to easily spot, track, and kill their prey through various means of hunting. In addition to their extreme eyesight, the birds have talons with specialized bumps known as spicules to maximise gripping abilities during flight. Their talons are also extremely sharp, so their prey is even more efficiently gripped with their great strength. The Bald Eagles prey consists of animals only. More specifically, their diet consists of fish, geese, ducks, snakes, rabbits, and rodents as well as other smaller birds (Dyer, “2017”). With the birds large appetite for small animals in mind, Eagles are considered to be medium sized Animalia.
Bald Eagles are not only notorious for their size, but their beauty. Contrary to common knowledge, Bald Eagles are not actually bald! However, adults bare white feathers on their head and tail which highly contrast and compliment their dark brown body. To top this off, they have a large curved yellow bill, and talons capable of inflicting mass damage to prey (Seaworld Parks & entertainment, “2018”). These two adaptations in specific are geared towards their self defense as well as hunting abilities. The talons and beak highly effective weapons as the birds lacks primary predators aside from us humans.
Their body shape resembles that of a hawk, with a large head making them bilaterally symmetrical like most birds (Cornell University, “2015”). Younger birds on the other hand, which are referred to as juveniles, do not bear such pattern. Instead, they have blotchy, and randomly dispersed patches of white pigmented feathers throughout their tail, body, and head. Socially, bald eagles engage in a multitude of different courtship rituals in order to form a bond between a pair. Cartwheels and chase displays as well as rollercoaster fights are examples of said courtship rituals.
Once a pair of birds has formed, the two are then generally bound for life with a separation rate as low as 5 percent. When the female is ready to mate, she initiates the sexual intercourse through a bow to her partner. The male partner will then mount the female from behind and internally fertilize her eggs. Once the oviparous eggs have been laid, the pair will remain in the nest to incubate the eggs together until they hatch 35 days later (Castro, “2016”).
Once hatched, the female will spend 90 percent of her time in the nest while the male will only spend 50 percent of his time in the nest until the young is able remain self sufficient. However, until this is the case, the young will be fed a diet of raw meat starting directly after birth. Unlike other birds, the parents will not regurgitate the food for their young but instead bring it to the nest with their talons. While the parents are the birds who take care of their young, no other birds are involved in the raising of the chicks (Nye, “2018”). Once these chicks have grown up, they are considered to be sexually mature once their white head and tail have developed which generally takes place in anywhere from four to five years. However, when mating rituals and acts are not taking place, Bald Eagles nest in colonies and have a clumped social distribution (Castro, “2016”). Bald Eagles are an ideal example of what a predatory bird should be like due to a host of adaptations which are geared towards allowing them to flourish in their environment. In detail, the birds have developed an incredibly large wingspan allowing them to catch air currents and drift through the air with minimal effort and energy.
Due to the birds spending so much time in direct sunlight, they have developed a bony ridge above the eyes in order to block the harsh sunlight (Corona,”2017″). Eagles are also K-strategists when it comes to their offspring as they only have 1-3 young annually. This makes them iteroparous birds as they reproduce multiple times before they die (Nye, “2018”). Their low hatch rates allows for maximum attentive care can to be taken by the parents resulting in a high survival rate of young. Reproductive rates and times are variable dependant on the region and climate in which the bird resides.
Universally, for all Bald Eagles, breeding takes place once per year (National eagle center, “2017”). In the wilderness, Bald Eagles have a typical life span of 20 to 30 years. However, while in captivity, Bald Eagles have been recorded to live up to ages over 50 years old (National eagle center, “2017”). This is likely due to the many impacts that humans have had on their natural environments due to mass deforestation and pollution. More specifically, Bald Eagles almost went extinct due to the over use of DDT, which is harmful chemical that was used to prevent mosquitoes from spreading malaria (U.S. fish and wildlife service, “2015”). The chemical caused the birds highly enfrently laid eggs to remain soft following the hatch and as a result of calcification not taking place, the eggs would then soon die off.
This die off of the chicks before their birth nearly caused the species to go extinct. If the bird was to have gone extinct, the food chain would have been affected as Bald Eagles predatory nature keep rodents and other animals which are prone to overpopulation in check by remaining atop of the food chain. With this in mind, it is clear that Bald Eagles are essential to the environment as a natural predator and without them, a collapse in the food chain could take place. Bibliography Websites used:Canadian Geographic. (2006, August 14). Animal Facts: Bald Eagle.
Retrieved January 31, 2018, from https://www.ca