The Magnificence that is the Arctic Tern
Updated: Nov 18, 2022
It’s a rather unremarkable bird to look at.
Visually, there are birds that are far more striking than the Arctic tern, with its white and grey body, a black ‘cap’. The only relief to this rather dull set of colours come from its blood red beak.
Its size won’t light up eyes either.
It’s a slender bird, its length ranging between 10-16 inches and weighing a slight 100 gms or so. I read somewhere that, its weight is similar to a single banana.
Yes. Definitely underwhelming.
There are so many birds that are far more impressive in size and colour.
They are sleek. I love watching them. But, truth be told...nothing spectacular
However, its the deeds of the Arctic Tern that catapult them to a different league altogether and why I find them so amazing.
We have heard of migratory birds but if there is a true Champion of Migrations, it is the Arctic tern. It is estimated to cover anywhere between 70,000 to 90,000 kms each year. Their average life span is around 30 years, so do the math on their lifetime mileage.
In case, those numbers don’t mean much, let me try to paint a picture. Through their life, the Arctic tern flies a distance that is equivalent to flying from the Earth to the Moon…three to four times !!
Check their size again.
The Arctic Tern tends to digress from a straight path between the Poles depending on food and weather
So, how does the tern cover such humungous distances ? And why ?
The simple reason how these long distances are covered is that the Arctic Tern prefers the summers and shuttles between Antarctica and the Arctic in order to catch the summer months in both the Poles. They fly round the year, back and forth between the Arctic and the Antarctic poles.
Around September to November, as the summer months come to an end in the Arctic, they start making their trip from the Arctic down South. They will stay in Antarctica till around March and then start northwards from April.
This is how a pleasant summer day looks for the Tern !!
While going south, they are quite relaxed, often digressing into routes that will give them better food and weather, sometimes taking a leisurely 90 days to reach their destination. While returning to the north, however, they appear to be far more purposeful, finishing the journey in half the time. I guess the urge to nest and breed might be driving this urgency.
In case, you are wondering why the tern goes through all this effort, the reason is simple – food.
The terns fish by sight, diving into the waters to pick up the small fish. In winters, the waters get too dark for them and their ability to see the fish and hence feed, gets badly impacted. It becomes easier to simply follow the sun.
Its a sight to watch them identify a group of fish and relentlessly dive in and feed
Now, to the part about Nature that truly fascinates me the most.
How Nature has designed the Arctic tern to cover these jaw dropping, mind numbing distances.
The Arctic tern has ‘pneumatic bones’ - bones that are hollow and filled with air. This naturally decreases the overall bodyweight of the bird, making it easier to fly. Add to it, a perfectly streamlined body.
The arctic terns’ wings have ‘high aspect ratio’. This means they are longer and narrower than is usually the case. Their shape reduces how much energy the birds spend when flying, whilst increasing how long they can remain in-flight. This could explain why they cover quite a bit of their journey gliding rather than flapping their wings. ( By the way, they also catch up on their sleep while gliding. )
Terns are aggressive defenders of their nesting areas. Here a tern is sounding off a clear warning
They have tricks beyond what Nature has provided them. Their flight is naturally a lot over water, but they follow the fish and that means that a quick snack is never too far away.
Fascinating, isn't it ?
The things that happen in the world around us !
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