Last year I was introduced by Joe Ordoñez to the world of Arctic terns (Sterna paradisaea, what a name). Skagway is a breeding ground for these amazing birds. They are rarely seen on land. Most of their life they spent in the air or on the ocean.
It has been known for a while that they breed in the arctic region and then migrate South to spend winter (the antarctic summer) in the antarctic. That’s a long way to travel each year. When scientist fitted 50 terns with location data loggers and analyzed the data after one year they were in for a surprise! Instead of the 40,000 km, as previously thought, the terns took a number of side trips, presumably to feed, which increased their annual journey by another 30,000 km. Since terns are long-lived birds (30 years) these 100 gram light flying machines travel in their life time the distance to the moon THREE times!
Interestingly, they don’t take the same route traveling north and south. Coming back from Antarctica they cover 20,000 km in only 40 days. That’s 500 km a day! Obviously they know how to use prevailing winds to their advantage.
Most of their travel is along coast lines. That means they are rarely spotted on land. Here in Skagway they decided to breed inside a petrol tank farm, or was it the other way around. and the tank farm was built at their breeding ground? Despite the unlikely environment, a good number of birds return every year and exhibit their delicate courtship behavior. This includes an aerial dance, the presentation of a fish, and a lot of noise. If they were more colorful you could think they are related to parrots.
All the details can be found for free in this PNAS publication.
You can imagine, that it is challenging to photograph such a swift flyer. Over the next month or so , we can practice, as they will mate, feed and protect their young. The young will hatch after a month in the egg, learn to fly within 2-3 days, and take off for their long journey south in September.