When you think of a bird’s nest, do you think of a little structure of twigs hidden away in a tree? That may work for some birds, but seabirds take the opposite approach, opting for crowds like New York at rush hour.
The weather over Kachemak Bay surrounding Homer was not promising, overcast and with a reminder of yesterday’s freezing, but we set off for the Barren Islands anyway.
As we headed out over the bounding main, we started seeing birds we hadn’t from shore. The silvery darts of sparrow-sized phalaropes flashed just above the waves. The chunky, rubber-ducky shapes of marbled murrelets bobbed before they dove away from the boat.
While many land birds rely on covert nests to raise their chicks, seabirds need a different strategy. It’s very difficult to be covert when the flat ocean extends in every direction, with no place to hide. So seabirds such as black-legged kittiwakes (a type of small gull), common murres (seabirds that are black with white bellies), and tufted puffins (with their long, golden eyebrow plumes) opt for safety in numbers on what to humans seem like inhospitable cliffs and rocks. Near Sitka, St. Lazaria Island of the Alaska Maritime National Wildlife Refuge is such a colony. Also part of the refuge, the Barren Islands are another colony just a couple hours’ boat ride from Homer.
As the Barren Islands solidified from the distance, we spied the white specks of kittiwakes swirling like a shaken snow globe. As we pulled close, we spotted thousands of kittiwakes crowded onto skimpy cliffs where they had to snuggle up to the rock wall to perch. When the dark shape of an eagle swooped past, birds flung themselves into the air by the thousands, their cries like a wall of noise.
Other birds weren’t as far into nesting season yet. Common murres floated on the water in long, tightly packed squadrons of hundreds, although some trendsetters perched on the dark cliffs. The murres’ honking added to the cacophony. Scattered across the water in pairs or loose flocks, tufted puffins eyed our boat warily. Others bombed past like black footballs with wings.
Although it seems like chaos, if you examine the locations of the birds on the cliffs, you’ll find subtle preferences. Common murres find a cliff ledge just big enough for a pair to stand. Kittiwakes prefer ledges a little wider where they can construct a nest. Tufted puffins prefer penthouse suites, burrowing into soil under grassy cliff-tops.
The eggs of each of these birds are specially shaped for their own style of precarious beginnings. Take a chicken egg, for example: While you can tell the narrow end from the wider end, the difference is slight. If you roll a chicken egg, it follows a wide circle with the narrow end pointed at the center. This keeps the egg from rolling away from the hen when she turns it.
Tufted Puffin eggs are the closest in shape to chicken eggs, of these three seabirds, but slightly more pointed on the narrow end. For puffins, snugging their eggs away in a burrow removes the concern of rolling off a cliff.
Kittiwake eggs are more elongated, tapering to the narrow end. The pointier, narrow end of the egg causes it to roll in a tighter circle. Although, in a nest, kittiwake eggs need to roll in a way that keeps them within nest boundaries.
Common murre eggs have an exaggerated shape, like someone morphed the image of a chicken egg on a computer, with a long, cone-shaped narrow end. This means they roll in a very tight circle; much better for a narrow nesting ledge. Since murres don’t go to the trouble of constructing a nest, they lay their eggs on bare rock. The shells of murre eggs are thicker than landbird eggs, to withstand being rolled around or pressed onto a rock when the parents incubate.
Of these three species, tufted puffins go to the most trouble when it comes to home-building. They use their strong feet — and sometimes their bills — to excavate burrows below the grassy brows of the islands where they nest. The burrows can extend about three feet underground. The cagey puffins include a bend in the tunnel about a third of the way in. Solid construction is worth the effort, since the burrows are reused from year to year, often by the same birds.
Both puffin parents incubate their single egg. The chick stays in this snug home until about the end of August. The chick’s parents fly far and wide to find fish for the growing youngster. Like many seabirds, how quickly the puffin chick grows depends on how much food the parents can bring home.
For the first several days after it hatches, covered in fluffy down, the puffin chick’s parents take turns keeping the chick warm, also called “brooding” it. After only about four or five days, the chick has grown large enough that it can be left alone for longer periods. The parents can leave to forage during the day, although one will stay with the chick overnight.
When it is big enough, the puffin chick will leave the burrow for the first and last time at dusk or in the dead of night. Although smaller than an adult, the young puffin’s legs are almost full-grown, all the better to swim with. It’s important that the chick starts out self-sufficient: Puffin parents have a “don’t let the door hit you on the way out” policy when it comes to letting their chick step out into the world.
Black-legged kittiwakes prefer an open air nest. They start with a foundation of mud and plants, then sculpt the bowl of the nest out of mud and plants or seaweed. They lay one to three eggs with both parents sharing egg-sitting duty. The chicks hatch covered in fluffy down, and in about a week, they no longer rely on parents to keep them warm. The chicks instinctively turn toward the cliff face or sit sideways, staying within the safety zone of the nest.
It may not be that safe, however. Older chicks will often attack siblings that hatched later, at the least taking more food. This often contributes to the demise of the younger sibling, although some flee to a neighbor’s nest where another pair of adults may act as adoptive parents.
Kittiwakes who survive until fledging are often unwilling to move away from home. As they are learning to fly, they continue to roost near their nest. They still beg for food from the parents, although most parents practice tough love and make the chick forage on its own. Some youngsters still hang around even when the adults have left the nesting colony for the year.
At first glance, with their minimalist nests of a few pebbles, common murres seem like careless parents. They, however, are the most attentive of the three and in an unusual way.
Life starts out rocky for murre chicks — literally. Murres crowd together, sometimes almost shoulder-to-shoulder, on the nesting cliffs. Like an efficiency apartment, the only territory they have is the personal space of both birds in a pair. The adults don’t even really “sit” on their single egg, they lean against the cliff wall while incubating.
The whole colony starts nesting on the same schedule, on the principle that there is safety in numbers. The more chicks there are at once, the more will survive hungry gulls and other predators. Murres are covered in fluffy down when they hatch, with extremely large legs and feet for their size. They turn away from light, attracted to the dark safety of the cliff face.
At about ten days old, the chicks can keep themselves warm. About three or four weeks after hatching, something dramatic happens. Great gatherings of male murres converge at the base of the nesting cliffs, calling for their chicks. Soon, even though they are not even close to full-grown, as dusk falls the chicks start leaving the nest, often leaping and trying to slow the fall by flapping their stubby wings.
When the chick reaches the water, father and chick call until they locate each other. The chick’s oversize feet help it paddle around. The father will now escort his offspring to feeding grounds away from the colony with hungry predators patrolling the sky. He will watch over the chick for another month or two. Being a good dad, he makes sure the chick has enough to eat and protects it until it’s big enough to survive on its own.
• Beth Peluso is a freelance writer, illustrator and avid birder. She enjoys spying on wildlife across Alaska.