"Haliaeetus Leucocephalus" latin for "white headed sea eagle". The name 'Bald Eagle' came from early colonists when "balde" meant white and not hairless.
Bald Eagles are one of the largest raptors found on our planet, and arguably the most majestic. Over 70% of them are found in British Columbia and Alaska. Every Fall Squamish in BC becomes home to one of the largest gatherings of Bald Eagles on our planet. At the start of October each year, more than 10,000 Salmon begin their annual journey upstream to spawn. This attracts one of their main predators...the Bald Eagle. Between October and the start of January over 1,300 Bald Eagles congregate in the large trees around the Squamish river systems. Here they take shelter during the winter months to feed on their favourite food, Salmon.
Bald Eagle Quick Facts
Scientific Name : Haliaeetus leucocephalus
Diet : Carnivore
Weight : 6-14 pounds
Wingspan : Up to 2.5m (8ft)
Sight : Can see 4-5 times further than humans
Lifespan : 20-30yrs (in the wild)
Speed : Flight 20-40mph (Dive speed up to 100mph)
Maturity : 4-5yrs
Did you know?!
They can reach altitudes of over 10,000ft!
Their eyesight is over 8x stronger than ours.
Their grip strength is a huge 400psi.
Their nests are the largest in the world and known as 'aeries'.
When they lose a feather on one wing they will automatically lose a matching feather on the other wing to remain 'balanced' in flight.
Size & Shape
Bald Eagles range in weight from 6-14 pounds with a huge wingspan of up to 2.5m! Females tend to be larger than males.
Maturity
They have an iconic appearance of mostly brown body with distinctive white head, neck and tail. Their irises, feet and beak are all yellow. This full plumage only occurs once the individual reaches maturity which tends to be around 4-5 years old. Prior to this they're mostly mottled brown with white blotches.
Communication
Although they're huge apex predators of the skies, their calls are somewhat weak-sounding. This series of high pitched whistling is usually accompanied with a vertical head toss. In films the use of a Red-tailed Hawk call is usually used for Bald Eagles as its a much more intimidating sound.
Food
Bald Eagles have adapted incredibly well over the years and have two main 'weapons'. Their sharp pointed beaks are perfectly designed for ripping and tearing their prey. Their powerful legs are equipped with large talons used to kill their prey on impact.
Despite Eagles being such powerful and dominant predators, they're actually opportunistic hunters. Their food of choice is fish (usually salmon) and so are usually found in regions with abundant fish populations and good tree coverage. Rather than hunt their own food it is very normal to witness a Bald Eagle scavenging from other hunters such as Ospreys and other birds. They will wait for them to make a catch and then move in to pester them using their overpowering size and strength to steal the kill from the smaller raptor. As well as this, Bald Eagles are more than happy to feed on Carrion from other animal kills. When they do hunt for themselves they don't dive down into the water systems like an Osprey, but instead swoop down and 'pluck' fish from close to the surface.
They also eat other birds, particularly sea birds, and smaller mammals such as rabbits and squirrels.
Habitat
They're distributed from Canada's boreal forests down to northern Mexico, covering a range of around 2.5 million square kms. Their habitat is influenced by three main things: food supply, nesting sites and freedom from disturbance. During the winter months Bald Eagles congregate along rivers and bodies of water that do not freeze over, that also contain sufficient food supplies to see them through the colder months.
Social Structure
Bald Eagles mate for life and tend to strengthen their bonds with amazing flight displays.
Conservation
Bald Eagles are currently listed as a 'Least Concern' due to their healthy populations today, although this hasn't always been the case.
In 1782 the Bald Eagle was declared the American national symbol, and at this time their numbers were in the hundreds of thousands. Due to illegal hunting, habitat loss, lead poisoning and the devastating impacts of pesticide DDT in their prey reduced their numbers to 417 pairs. Despite the US governments Bald Eagle Protection Act of 1940 making it illegal to kill these birds, this had little affect on the declining numbers.
The biggest contributor to their decline was the effects of pesticide DDT. This pesticide was introduced shortly after World War II and become widespread in the agricultural world very quickly. DDT builds up in the birds tissues and affects the formation of the shell of their eggs. They form thin and weak leading to fewer young being produced. It took until 1972 to ban the use of DDT and by 1978 the US declared their national bird as Endangered.
The banning of DDT did allow for a successful recovery for the Bald Eagle across the US in particular. They were taken off the endangered species list by 2007 and now they're more than 11,000 nesting pairs in the lower 48 US states. BC alone has an estimated 20,000 Bald Eagles.
Although the banning of DDT has allowed numbers to bounce back, our planets Bald Eagle populations still face threats from human impacts, specifically through hunting and habitat loss.
Protecting important Bald Eagle habitats combined with public education not only helps to protect Bald Eagle numbers but also benefits many other species and has a positive impact on the overall ecosystem.
Eagle Watch
Eagle Watch was established in 1995 to aid the protection of wintering Bald Eagles and overall ecosystem of the Squamish Valley. It is coordinated by the Squamish Environment Society (SES) which is run by volunteers.
Throughout the peak season for wintering Bald Eagles volunteers count (twice daily) and record Eagle numbers. This helps track the annual fluctuations and patterns of Bald Eagles year on year and allows us to assess the overall health of this ecosystem.
If you're interested in becoming a volunteer you can find out more here: https://www.squamishenvironment.ca/programs/eaglewatch/
A few helpful sources: