Ontogeny: How does migration aid Arctic Tern development?

Cartoon of Bird Development

© Courtesy of  www.kingdomcounty.com/ontogeny.jpg

Arctic Terns nest in arctic belt, during the arctic summers. They then move down to the Southern Hemisphere, specifically the Antarctic during the Southern Hemisphere summer. When their  time is up they make their way back to the Arctic , thus the circumnavigate the Atlantic

The migratory behavior the Arctic Tern is hinged on its breeding and nesting behaviors. Terns breed in Arctic regions during the Northern Hemisphere's summer. There the warm weather provides the nesting birds with an abundance of food, particularly insects and  crustaceans. The warm weather and seemingly endless days allow nesting parents to feed and nurture their young.

As summer draws to a close and the temperature changes and the days shorten drastically, food sources which are dependent on the warm waters of the Arctic Ocean, become scarce. Hence, parents and well fed juveniles carry out the first leg of the migration process to the Antarctic. There juveniles  will remain for the next two years to full mature. This region is so favored even outside of its summer period because even with the season changes, there is little variation in day light hours.

When juveniles are fully matured into adults , which is a period of about two years they will then journey back to their original breeding grounds (Ref**).

The exact mechanism by which individuals of this species are able to make their way over nearly 22000 miles of open ocean to their original breeding grounds in the arctic is still under research.

It should be noted that the urge to migrate is triggered by hormonal changes in the birds body, as its internal clock indicates that it is time to travel. The internal clock is believed to be triggered by changes in weather, length of day and the availability of food supplies (Ref**).

Juvenile Tern

© Courtesy of Michael Steciuk