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Murrelets: Mystery in plain sight

TIP: If you spy closely, you can decode the differences between Southeast Alaska's two species of murrelets

Posted: August 16, 2013 - 12:01am
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A group of Kittlitz's murrelets paddle around the waters of Glacier Bay. Kittlitz's murrelets search out mountain fortresses where glaciers have recently peeled back to reveal bare rock. Their nests often lie in a crevice or downhill from a boulder to protect the chick from wind or loose rocks bouncing downslope.  Courtesy of Beth Peluso
Courtesy of Beth Peluso
A group of Kittlitz's murrelets paddle around the waters of Glacier Bay. Kittlitz's murrelets search out mountain fortresses where glaciers have recently peeled back to reveal bare rock. Their nests often lie in a crevice or downhill from a boulder to protect the chick from wind or loose rocks bouncing downslope.

This wildlife spy stowed away on a Southeast Alaska cruise around Admiralty Island under the guise of a naturalist aboard the Safari Endeavor at the end of July. Under amazingly clear skies, amidst the humpbacks and harbor seals, I had a close-up look at two of Southeast Alaska’s most mysterious seabirds: marbled murrelets and Kittlitz’s murrelets.

Marbled murrelets are one of Southeast Alaska’s most numerous seabirds, but like many stars, they prefer to keep their family life secret. Kittlitz’s murrelets are far less numerous and with their preference for glacier-scraped landscapes, harder to find. The Kittlitz’s murrelet looks very similar to its more numerous marbled murrelet cousin, but an attentive wildlife spy can distinguish the differences.

The first clue is habitat. Kittlitz’s murrelets, found only in Alaska and eastern Russia, feed mostly in the turquoise water near glaciers. Glacier Bay is a fantastic place to see them. Strong, agile swimmers, their wings propel them in underwater pursuit of small fish. Marbled murrelets are much less picky about where they feed, sprinkling themselves liberally across the waters of Southeast. While our boat was still docked, we could see them, their distinctive no-neck, rubber-ducky silhouettes bobbing in Gastineau Channel. In Icy Strait, there were dozens in small groups.

Most seabirds prefer to nest in crowded, noisy (and noisome) colonies with thousands of their closest friends. This provides many eyes watch for predators and allies to help chase predators away. If an intruder does attack, the crowds make it more difficult to single out a victim.

Kittlitz’s and marbled murrelets employ a different strategy; their summer colors give a clue to their plan. Each pair raises a single chick, like many seabirds, but they hide their nests in isolation, relying on secrecy instead of numbers to protect vulnerable babies.

Seabirds that live on or near the water are usually boldly-patterned with black, gray, or white. Common murres and gulls are variations on this theme. White, seen from underwater, blends into the backlit water surface; seen from above, gray and black merge with the moving water surface.

Our two suspect murrelets are black-and-white in winter, but the summer marbled murrelets we spotted were dark brown, while Kittlitz’s murrelets had a salt-and-pepper mix of brown, gold and white. Depending on the light and weather, the overall color of marbled and Kittlitz’s murrelets can be difficult to distinguish. Look at the pattern. Marbled murrelets sitting on the water are a fairly uniform brown. Kittlitz’s have a more speckled look. When flying, marbled murrelets might be slightly paler on the belly, but there’s not a distinct contrast. Kittlitz’s murrelets, however, often have a crisp white belly that catches the eye as they rocket past.

The colors, though similar, reflect their different habitat choices for nesting. Marbled murrelets seek mossy green bowers in towering old growth trees, although occasionally a mossy nook on the forest floor or cliff will do. Their dark brown feathers blend into the tree bark, and their chicks have fluffy, tan and brown speckled down. Kittlitz’s murrelets search out mountain fortresses where glaciers have recently peeled back to reveal bare rock. Their nests often lie in a crevice or downhill from a boulder to protect the chick from wind or loose rocks bouncing downslope. Kittlitz’s murrelet chicks have more gray tones to their spotted down.

Murrelets are stealthy about returning to the nest to feed their chicks. If you spot a murrelet lounging on the water holding a silvery fish in its bill, it’s waiting for twilight to zip back to the nest under the radar of predators. Adults eat the fish they catch for themselves, so a bird carrying a fish is a dead giveaway it has a chick hidden somewhere. Parents leave the nest before dawn, commuting to the best feeding areas without betraying nest locations. Their strong wings help them reach high speeds, from a cruising speed of 40 miles per hour up to 100 miles per hour. Birds that nest near Mendenhall Glacier have been tracked to Glacier Bay on their daily commute.

When the chick is old enough, the parents practice tough love: once the chick leaves the nest, it’s on its own. About a day before a chick departs, it plucks out its down, revealing the ocean-ready black-and-white juvenile fathers. It flaps and paces restlessly until it finally takes to the air for the first time and flies to the ocean, sometimes many miles away. Not quite full size, the youngster must figure out how to swim, catch fish and avoid predators to survive.

Another detail to look for to distinguish these similar species is … the tail. (Since the most common view I’ve had of murrelets is as they fly or dive away, this tail trick is handy.) Both birds have a stubby tail with very short feathers you can see spread out when they fly. On marbled murrelets, all the tail feathers are dark brown; on Kittlitz’s murrelets, the outer tail feathers are white. Careful though, marbled murrelets sometimes have whitish patches wrapping around their flanks, but above the actual tail feathers.

If you can sneak a closer peek with binoculars, there is another difference. The bill of the marbled murrelet looks longer. Kittlitz’s murrelets have feathers covering the majority of their bills, so it looks stubby. This is a bit of subterfuge, because both birds can open their bills very wide to snatch fish. It’s possible the extensive feathering prevents the Kittlitz’s murrelets from radiating too much body heat in glacial waters.

Adults of both species don’t start changing into winter colors until about August, and the transition can take months. The completely black-and-white birds we saw frequently on the water during our late July cruise were juveniles. Some that we saw while kayaking seemed uncertain how to respond. Unlike the adults that dove before we got too close, the inexperienced young birds often seemed indecisive, waiting longer to dive.

The juvenile (and winter) colors of these birds make them much easier to tell apart. Marbled murrelets have a black hood that covers the head and ends below the eyes. The dark hood on Kittlitz’s murrelets stops above the eye, leaving the eye plainly visible against white cheeks.

With these clues — habitat, voice and body and tail color patterns — in your bag of tricks, if you look closely you can unmask the identity of murrelets, especially near glaciers. They may look dull to the uninformed, but you’ll know the quietly amazing lives of these seabirds.

 

• Beth Peluso is a freelance writer, illustrator, and avid birder. She enjoys spying on wildlife around Alaska.

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