Endangered Spotlight: Marbled Murrelet (Brachyramphus marmoratus)

By Hannah Orlove

Marbled Murrelet
Credit: NOAA

You might not expect a bird that spends most of its life out on the ocean to nest dozens of miles inland, high up in the trees. But that’s where the Marbled Murrelet lays its egg.

After all, what safer nesting spot is there than hundreds of feet up a tree in an old-growth forest? Just because they’re a pelagic species doesn’t mean they can’t keep a nice summer home in the woods.

Marbled Murrelets nest on a platform of moss, lichen or pine needles, and are very good at blending their homes in with their surroundings. Because the nests are so high up, and so difficult to spot from both the ground and the air, people didn’t know Murrelets nested in trees until 1974.

Unlike other birds in the auk family, Marbled Murrelets do not nest in colonies. Their homes are isolated and secluded in the forest. Each breeding pair lays a single egg.  It takes about a month for the egg to hatch and 40 days for the chick to fledge. Unfortunately, overall breeding success is low; the chicks never have an easy time getting from land to the ocean, where they will spend most of their adult lives.

Description

Marbled Murrelets are small seabirds; they are about ten inches in length and weigh about half a pound.  They dive and forage for food both day and night. Their diet cosists mostly of fish, but can include crustaceans and amphibians. Like many bird species, they’re devoutly monogamous.

Their name comes from their plumage, which changes several times during their lives. It starts out as fuzzy and brown as chicks, and molts to a white underbelly and throat with mixed grey and black on their heads, necks, wings and backs. During the breeding seasons the plumage changes again, to an overall sooty brown-and-gray, while keeping the dark back and wings – hence the “marbled.”

They’re sometimes mistaken for Long-Billed or Kittlitz’s Murrelets, other birds in the same genus that have similar plumage and nesting habits. They were classified as the same species until about ten years ago, because of the similarities in plumage and behavior.

Endangered Habitat

Every summer Murrelets return to the forests to raise their chicks, and not just any forest: it has to be old-growth forests with tall trees and along the Northern Pacific coast of North America, from the Bering Sea to San Francisco.

Given that this sort of landscape is at a premium right now, along with the low overall success rate for the chicks, things aren’t really looking up for these little birds.  In addition, populations of predators such as rats and raccoons are skyrocketing along the coast. 

All in all, logging is considered the number one threat to Murrelets.  However, the birds have also been entangled in fishing nets and devastated by oil spills.  They’ve been federally listed as “threatened” since 1992. Hopefully, by protecting their coastal habitat, they will flourish again.