What does Kittlitz's murrelet have in common with tidewater glaciers? That is where this small seabird calls home. As Alaskan glaciers shrink, so do the number of Kittlitz's murrelets. Could the two be linked? In order to understand the possible links, an appreciation of the bird's natural history is essential.
Kittlitz's murrelet (Brachyramphus breviostris) was named by Heinrich von Kittlitz, a German naturalist and explorer who traveled to Alaskan waters on a Russian voyage from 1826-1829. Kittlitz's murrelet is found in Alaska and the Russian Far East and is also known as the "glacier murrelet." They are most frequently seen in the icy, swirling, murky waters near tidewater glaciers in places like Glacier Bay, Icy Bay and Prince William Sound. This small seabird is about the size of an adult human hand - 7.5 to 9.5 inches long. It is nondescript in color and usually found in family groups or pairs. It avoids predators (and humans) by quickly diving under water, and spends the majority of its time at sea. As a result, little was known about the abundance and occurrence of this bird until recently.
With surveys occurring more frequently in more areas came a closer estimate of population size. A decline in population was apparent with increased data and Kittlitz's murrelet is on the national and Alaska Audubon Watch list. Recently, the U.S. Fish and Wildlife Service has documented a pronounced decline in its population. In 2004, Kittlitz's murrelet was made a candidate species for endangered status.
Kittlitz's murrelet has an exciting lifestyle. It lives and breeds all summer in the "front yard" of tidewater glaciers. The murrelet is found most frequently in waters half covered by surface ice. It spends most of its time a couple hundred yards from shore during summer, and winters offshore in the open ocean. All of the North American population breeds, molts and winters in Alaska. A single egg is laid in nests on bare rock on steep slopes above timberline, often on talus slopes near glaciers. It may not breed until it is 2 to 4 years old. It eats small crustaceans and fish, such as capelin and herring.
Kittlitz's murrelet resembles the closely related marbled murrelet, which also lives in Alaska. Both are small brown birds in summer and show a black and white pattern in winter. The main identifying mark in summer is the white or pale outer tail feathers. The white plumage visible in flight is the best way to distinguish it from the marbled murrelet. In winter the best identifying mark is Kittlitz's white face and short bill. This is not a bird that is easy to tell apart from its more common relatives. That, in part, is why the decline in population was hard to show.
Evidence of a decline has been accumulating over the past decade. A substantial number died as a result of the Exxon Valdez oil spill. Since 1991, the population of Kittlitz's murrelets decreased by 80 percent in Glacier Bay and declined steadily in Prince William Sound. Although this species is difficult to count accurately, the current population is estimated at 10,000. The mystery of why the population is declining is the focus of current research. A critical factor is that this seabird lives and breeds in habitat that is shrinking every year. Tidewater glaciers are receding, changes occur in ocean currents, and their fish prey change distribution.
Kittlitz's murrelets have many factors affecting their lifestyle near tidewater glaciers. Their population is clumped in front of active glaciers, those places most attractive to summer tourists, and feed in areas harvested by commercial gillnetters. Most of the current population is found only where stable or advancing glaciers occur. More food may be available in stable glacial areas than in the siltier, less salty fjords where glaciers are retreating.
The Kittlitz's murrelets are vanishing, but the reasons are not yet understood. Perhaps with human help, the little glacier murrelet may still be around in another 200 years.
Brenda Wright is president of Juneau Audubon Society.
© 2018. All Rights Reserved. | Contact Us