Birds of Chignik Lake: Arctic Tern – World’s Migration Champion… and Vomerine Serrations?*

Arctic Tern Chignik Lake

With some Arctic Terns traveling nearly from pole to pole, no bird migrates further than representatives of this species. An interesting consequence of their affinity for spending summers at the poles is that it is also the case that no bird lives in more hours of daylight. (Chignik Lake, July 27, 2020)

“They’re pretty amazing.” We were watching a group of terns diving for small fish when one of us turned to the other and made the comment. Commanding the air with a combination of graceful soaring, swallow-like directional changes, Kestrel-esque hovering and pelagic seabird-style dives, as they called back and forth among themselves the terns almost seemed to be announcing, Watch! This is flying! There were few misses as they dramatically crashed the water and emerged with small, silvery fish in their bright red bills.

Arctic Tern bill serrations

As is the case with many dedicated piscivores, the bills of Arctic Terns feature serrations. But unlike the tomial serrations found on some ducks, in Arctic Terns they appear to be confined to the inside of the upper bill. They are thus analogous to vomerine teeth on the roof of a trout’s upper jaw.* These serrations aid in grasping and holding onto prey. (Chignik Lake, July 27, 2020)

For my own part, I no longer speculate as to whether or not birds experience feelings akin to human enjoyment in these successes. I’m certain they do.1 And the cries and calls of gregarious species such as terns seem to be at least partly aimed at sharing the good feelings that come with easy feeding on bountiful prey.

World-wide distribution, range and migration routes of the Arctic Tern: Map by Andreas Trepte, commons, Wikimedia

It depends on exactly where one is departing from and where one will end up, but a tern feeding along the Antarctic ice shelf in summertime down there and later migrating to Arctic Alaska to breed during summertime up there has to cover some 10,000 miles, making for a round trip of 20,000 miles. But that’s nothing. Arctic Terns don’t often take the most direct flight path; there are records of individuals traveling as much as 57,000 miles in a single year.

Arctic Tern feeding chick Alaska

Arctic Terns typically lay one to three buff-colored eggs in nests constructed on the ground. We found this devoted parent and its chick at Potter’s Marsh, a well-known birding sanctuary in Anchorage, Alaska. (June 21, 2017)

Given the context of their long flights over vast, open seas and their need to feed along the way, it is easy to understand how a bird such as a tern might mistake the glimmer of a small piece of plastic floating on the ocean for the flash of a fish. We can all help these birds by making certain that every bit of the plastic we use – every cigarette butt, candy wrapper and the rest of it – is disposed of properly. Arctic Terns are among the truly amazing beings we share this planet with, deserving of our admiration and respect.

Arctic Tern Range Map: with permission from The Cornell Lab of Ornithology, Birds of the World

Arctic Tern Sterna paradisaea
Order: Charadriiformes
Family: Laridae
Genus: Sterna – Old English stearn = tern
Species: paradisaea – Latin: paradisus = paradise

Status at Chignik Lake: Common in Summer on Black Lake and Chignik Lake

David Narver, Birds of the Chignik River Drainage, summers 1960-63: Abundant on Black Lake; Common on Chignik Lake

Alaska Peninsula and Becharof National Wildlife Refuge Bird List, 2010:
Common in Spring and Summer; Uncommon in Fall; Absent in Winter

Aniakchak National Monument and Preserve Bird List: Present

*Birds do have a vomer. However, although I checked several references I could find few mentions of this avian structure and no mention of “vomerine serrations.” I’d be interested to learn more about this fascinating anatomical feature.

1For further exploration of this subject, see: Emory & Clayton, Do Birds have the Capacity for Fun? Current Biology Volume 25 Issue 1. January 5, 2015

Table of Contents and Complete List of Birds of Chignik Lake

© Photographs, images and text by Jack Donachy unless otherwise noted.

For a list of reference materials used in this project, see: Birds of Chignik Lake