The Arctic Tern is the World Champion for migration.The It's a small bird, about 12 to 15 inches (30 to 38 centimeters) in length and weighing about 3.5 ounces (100 grams), but it makes the longest migration of any bird in the world. It travels about 44,100 miles (71,000 kilometers) annually — almost twice the circumference of the earth! — in its S-shaped migrations from Greenland to Antarctica and back. Over its average 34-year lifespan, it travels a total distance equivalent to three round-trips to the moon!
Among the most nomadic birds on the planet, these sun-loving tourists summer t a year during their ambitious routes
Because of their migratory pattern, Arctic terns see two summers every year and get more daylight than any other animal in the world.
Arctic terns have one of the longest-known migratory routes of all animals. Terns that nest in the Netherlands can travel over 90,000 km (55,900 miles) per year.
They travel an estimated 2.4 million km (1.491 million miles) in their lifetimes. That’s three round-trip flights to the Moon.
Right before a colony of Arctic terns take flight, they grow silent. This moment is referred to as the “dread.”
They do not spend the whole route of their migrations flapping their wings, but rather glide a great amount of the distances. Actually, they’re such good gliders they can even sleep while gliding.
Arctic terns are one of the only birds aside from the hummingbird that can hover.
Rather than take direct routes between the North and South Pole, Arctic terns detour long distances to find better feeding grounds or avoid inclement weather.
Every year, they migrate from the Northern Arctic areas where they live to Antarctica, where they spend the winter. Not all Arctic Terns live in the same place in the Arctic, so they don't all fly the same distance when they migrate. Scientists studying the Arctic Terns put tiny devices, called geolocators, on their legs so they could track the birds during their migration. What they learned was that one bird actually flew from the United Kingdom to Antarctica and then back, a distance of almost 60,000 miles!
Most Arctic Terns can find their way back to the place they were hatched!Males and females mate for life, and both the parents take part in raising their young. They are fiercely defensive of their chicks. Both parents take turns incubating the eggs and, after these hatch, they both bring food for the young until they are of age
Arctic terns have a very particular and extreme lifestyle, all the more surprising when you realize how small they are, they have a number of anatomical, behavioral and physiological adaptations that allow them to survive successfully.
Arctic Tern Adaptations:
Very high metabolic rate (physiological) - Many polar and cold climate birds deal with cold temperatures by consuming and burning food to generate heat from within. In order to do this they have to consume high energy food that is easily and quickly digestible. The fish and oily krill and other prey that terns feed on provide the readily accessible fuel that enables them to live their fast-paced life.
Dive bomb other animals that approach the nest, aiming at the head (behavioural) - Whether a potential predator or just some big clumsy animal that might trample the nest, eggs and chicks, they all come in for the same treatment. Arctic terns dive repeatedly at any animal (including man) that they think represents a threat. They call out in alarm and repeatedly attack from behind the head so they have maximum disorientation effect and are less likely to be harmed themselves. They keep going as long as they feel threatened and stop when the threat is sufficiently far away. Often you will have no idea where the nest actually is other than somewhere near where you were. A frantic term attack can leave even a polar bear with bloody wounds to the head!Flies from the Arctic to Antarctic and back again every year (behavioural) - Arctic Terns nest in the Arctic during the summer, when their young have fledged and become independent, they then fly to Antarctica (including the juveniles) where they winter during the Antarctic summer before flying back again to the Arctic to breed the following year. They do this to take advantage of food abundances at the peak times of year and to avoid food shortages at other times. They nest and rear their young all around the Arctic, though mainly fly south along an Atlantic route before spreading out again once in Antarctica.
Fantastic fliers - as you might imagine (anatomical and physiological) - Shaped with tail feathers that can be spread wide or pulled into a narrow dart to change aerodynamics in flight for covering distance or hovering and diving while feeding. Hollow bones for lightness. Able to sleep on the wing during migrations. Short legs that aid an aerodynamic shape in the air but make the birds rather clumsy on the ground
uploaded 11 jun, 2019 Copyright by George
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