Arctic Terns

Arctic Terns are the ultimate travelers. Each year they cross the globe twice; once in the spring, from Antarctica to arctic and sub-arctic regions in the circumpolar north, and then back in the fall. Each year they make this journey just to lay a couple of eggs and to try their best to successfully raise a brood of chicks. This is about a 70,900km round trip journey offshore every year, and is the longest known migration route of any migratory animal or bird in the world. They are very rarely seen over land during migration, as they prefer to take a winding offshore route instead.

Arctic Tern

Arctic Tern

Arctic Terns (Sterna paradisaea) are medium-sized seabirds, averaging at a length of 13-15inches with a 26-30inch wingspan. They live for 20 years on average, though some have reached the age of 30. They are grey and white birds that have a black cap on the head, a bright red bill, and bright red legs. Their wings are narrow and pointed, and they have a very wide,long forked tail. They stand out as obviously different when you watch them flying amongst the gulls, not just because of their appearance but also because of their flight pattern. Unlike the steady, and sometimes lazy-like wingbeats of a gull, Arctic Terns flap with quick, short, and aggressive wing-beats, pushing their wings slightly backward with every downward stroke. They have a sharp, grating call which you can hear here. They have a very aggressive temperament that is very effective when it comes to chasing predators (and humans!) away from their nests, chasing other terns out of the breeding territory, and stealing food away from gulls. They are typically carnivorous, eating small fish and crustaceans that they find in water, washed up on shore, or in the possession of other birds. They constantly fly over bodies of water, examining it with their sharp eyes for signs of food. If they spot something tasty, they pause, hovering in a slightly upright position to  take aim, and then dive into the water surface to snatch it up.

Arctic Tern Incubating Eggs

Arctic Tern Incubating Eggs

Arctic Terns usually start breeding 3 to 4 years after their birth, and mate for life. Courtship displays are very elaborate for a pair breeding for the first time; they do high flights which end with slow descents and the male feeding fish to the female, on ground struts, and circular flying patterns.  Interestingly, both the male and the female have equal say where the nest site will be, unlike most birds in which the female makes the final decision. The defence of the nest and the raising of the chicks is shared equally between both parents. It is common for terns to nest in colonies, and they like to have their nests in open places near water. I have seen Arctic Terns nesting on rocky islands out in big lakes, on rocky/sandy cliffs beside lakes, and on rocky/pebbly shores. An Arctic Tern nest is no more than a shallow scrape in the ground, with maybe a bit of grass or something similar lining the nest. An average of 2 eggs are lain, 3 maximum, and are brooded for 22 to 27 days by both parents.

Arctic Tern Eggs

Arctic Tern Eggs

The eggs are well camouflaged and greatly resemble rocks. Once the chicks hatch, they stay in the nest for only 1 to 3 days before setting out with their parent’s protection. For nests on lake shores, it is often a race to hatch the chicks before the rising water floods the nest, which makes the chick’s early mobility crucial to survival. It is also critical when it comes to avoiding predation; the nests are located in open, easy to spot areas with only the parents aggressive dive-bombs to protect the eggs. The parent’s aggressive attacks to anything that comes near is something that other birds such as shorebirds take advantage of. They will build their nests in close proximity to the tern nest, gaining a defence against predators that they would not otherwise have.

Semipalmated Plover

Semipalmated Plover

Semipalmated Plover Nest, Only Meters Away From A Tern Nest

Semipalmated Plover Nest, Only Meters Away From A Tern Nest

I was lucky enough to be able to watch a nest of Arctic Terns this spring after being informed of its location by our neighbours. I watched the eggs for a couple of weeks, and whenever I ventured too close the parents would come and dive-bomb my head. Nesting within meters of this nest was a pair of Semipalmated Plovers. One day, I came to check on them and found the tern’s chicks in the process of hatching. Two chicks had completely hatched, and were lying in the nest covered in wet down, while the third egg had been pushed out of the nest and was half-hatched. The next day there was no sign that anything had ever nested there, except for the odd white stain on the nearby rocks. The chicks had taken off running and their parents followed. Soon now they will all be flying down to Antarctica. It’s really amazing!

Arctic Tern Chicks

Arctic Tern Chicks, Freshly Hatched

The Legend of Fox and Tern

The Arctic Tern sits atop the mostly hidden mountain of floating ice and watches the brilliant tangerine sun teeter within twilight between risen and set.  The Arctic fox sees this and decides that he will have fun and play some games with the Tern.  So the Fox jumps atop a rock now face to face with the Tern but about one hundred yards apart separated by sea and floating ice.
“Why do you travel to distant places during the winter?” The Fox asks
“Well it’s because… ummm… well I am not sure but I just do.” the Tern firmly states.
“You seem so content sitting atop the glory of the iceberg and watching the sun bob up and down.  Why leave?” The fox questions with a smirk.
Now the Tern has never thought of why he leaves his throne of ice but he just does.  He thinks of flying and how tiring it can become.  And how comforting the cool Arctic breeze can be, and how the sight of the landscape is breathtaking.  So the Tern says.
“Well you know what Fox, I will try it this year and I will stay atop this perch of mine and watch the sun for the winter.”  He says proudly.
“That’s good for you Tern, trying something new.  I can’t wait to hear what you have to say about the winter.”
And the fox leaves with a smile and goes to hide in his hole until sun set and winter comes along.  The Tern waits and sits there peacefully.  When all of the other Tern’s leave this one just stays even after trying to persuade him otherwise.
The Winter comes along and the Tern, having never realized what the winter was like, becomes annoyed when the days become shorter and the sun is up in the sky less.  He doesn’t realize fully his mistake until it is too late.  The Tern has become frozen to the iceberg.
The Fox having realized this runs across the now ice solid sea sneaks up behind the Tern in the darkness and now has a new flavor for dinner.

That is why the Arctic Tern never stays for Winter, but instead travels to the Antarctic.

http://en.wikipedia.org/wiki/Arctic_Tern

http://www.allaboutbirds.org/guide/Arctic_Tern/id

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