Saturday 4 February 2023

MIGHTY KWIKW: BALD EAGLE

Bald Eagle / Kwikw / Haliaeetus leucocephalus
A mighty Bald Eagle sitting with wings spread looks to be controlling the weather with his will as much as being subject to it. This fellow has just taken a dip for his evening meal and is drying his feathers in the wind. 

As you can imagine, waterlogged feathers make flight difficult. Their wings are built for graceful soaring and gliding on updrafts of warm air called thermals. 

Their long feathers are slotted, easily separating so air flows smoothly and giving them the added benefit of soaring at slower speeds. 

As well as his wings, this fellow is also drying off his white head feathers. A bald eagle's white head can make it look bald from a distance but that is not where the name comes from. It is from the old English word balde, meaning white.

In the Kwak'wala language of the Kwakiutl First Nations of the Pacific Northwest — or Kwakwaka'wakw, speakers of Kwak'wala — an eagle is known as kwikw (kw-ee-kw) and an eagle's nest is called a kwigwat̕si

Should you encounter an eagle and wish to greet them in Kwak'wala, you would just say yo. Yup, just yo. They would like your yo hello better if you offered them some fresh fish. They dine on all sorts of small mammals, fish and birds but are especially fond of pink salmon or ha̱nu'n (han-oon).

These living dinosaurs are a true homage to their lineage. They soar our skies with effortless grace. Agile, violent and beautiful, these highly specialized predators can catch falling prey mid-flight and dive-bomb into rivers to snag delicious salmon. 

Their beauty and agility are millions of years in the making. From their skeletal structure to their blood cells, today’s birds share a surprising evolutionary foundation with reptiles. 

Between 144 million and 66 million years ago, during the Mesozoic era, we see the first birds evolve. Eventually, tens of millions of years ago, an ancient group of birds called kites developed. Like today’s bald eagle, early kites are thought to have scavenged and hunted fish.

About 36 million years ago, the first eagles descended from kites, their smaller cousins. First to appear were the early sea eagles, which — like kites — continued to prey on fish and whose feet were free of feathers, along with booted eagles, which had feathers below the knee. Fossils of Bald Eagles are very rare and date to the late Pleistocene. Eagles are known from the early Pleistocene of Florida, but they are extinct species not closely related to the bald eagle.

Like the kites, bald eagles have featherless feet, but they also developed a range of other impressive adaptations that help them hunt fish and fowl in a watery environment. Each foot has four powerful toes with sharp talons. Tiny projections on the bottom of their feet called “spicules” help bald eagles grasp their prey. A bald eagle also has serrations on the roof of its mouth that help it hold slippery fish, and incredibly, the black pigment in its wing feathers strengthens them against breakage when they dive head first into water.

Obviously, there is much more than their striking white heads that sets these iconic raptors apart from the crowd. Their incredible physiology, built for life near the water, is literally millions of years in the making.