Scientists estimate that 40 to 50,000 of these birds live in the wild. Marbled murrelets are small seabirds that weighs about 200 grams. In the southern part of the range, pairs appear to nest solitarily, but farther north, pairs may nest fairly close together. Predators of murrelet nests in-cluded Common Ravens ( Corvus corax) and Steller’s Jays ( Cyanocitta stelleri ); predation of a nest by a Great Horned Owl ( Bubo virginianus) was also suspected. The plumage of fledged young is similar to that of adults in winter. In the northern part of the range, they often feed heavily, especially in spring, on zooplankton—tiny shrimplike crustaceans called euphausiids, mysids, and amphipods. Lutmerding, J. In The Birds of North America (P. G. Rodewald, editor). Records from interior lakes and forests in late winter could be of birds displaced from the ocean by storms or possibly birds that are prospecting for nest sites. Cornell Lab of Ornithology, Ithaca, New York, USA. They swim and call in unison, then dive and surface simultaneously, repeating their sky-pointing display. To nest, they fly up to 70 kilometres inland and lay one egg on a large moss-covered branch high up in a coastal temperate rainforest tree. The marbled murrelet is a small Pacific seabird belonging to the family Alcidae. Because they forage near shore, many Marbled Murrelets have died as a result of oil spills and other marine contamination. During summer in the Pacific Northwest, they also forage in freshwater lakes, where they take juvenile and larval fish. Marbled Murrelets make tree nests on large, moss- and lichen-covered branches high (usually over 40 feet) above the ground in mature and old-growth coniferous forest, normally in the largest tree in the area. Kushlan, J. Murrelets hunt and fly at night to avoid leading predators to the nest. Pale olive green to greenish yellow, spotted with black, brown, or purple. Chicks are downy and tan colored with dark speckling. At the end of the breeding season, large flocks may gather in the northern part of the range, up to about 5,000 birds, and in areas of greatest abundance they remain social through much of the nonbreeding season. In the winter they are black with white underparts and in the summer they are brown with mottled white and brown on their throat, chest and abdomen. No actual nest is built. The partner then comes to swim side by side, and both extend the necks, then point the bills skyward, giving soft calls. In late winter and early spring, Marbled Murrelets court at sea, and that courtship continues into summer. Courtship behavior may continue year-round, and scientists suspect that monogamous pair bonds are maintained through the nonbreeding season. Both parents feed the young chick. The Marbled Murrelet’s breeding habitat requirements have been the subject of intense study since the first nests were discovered in the 1970s. The first nests in North America were found in the 1970s, with the surprising discovery that these murrelets nest high in old-growth trees of the Pacific Coast. Like many seabirds, they gather at dawn and dusk on the ocean nearest the nest site. They dive quickly, opening the wings to “fly” underwater, steering with both wings and feet in rapid pursuit of prey. Steller's jays (Cyanocitta stelleri) and common ravens (Corvus corax) prey on marbled murrelet eggs and nestlings. Multiple studies suggest that they forage cooperatively, herding small fish together as a team to make capturing them more efficient. Adults eat smaller prey but feed their young larger (up to 4.3-inch-long) fish, which they capture mostly at dusk and dawn. Marbled murrelets’ main predators are ravens, crows, jays, owls and hawks but they are also threatened by logging in nesting habitats, oil spills, and entanglement in fishing nets. (1997). They are found in Asia, Alaska and the Pacific Northwest. After it fledges, the young bird flies to the ocean by itself, where it eventually joins others of its species. They spend most of their lives at sea eating Pacific sand lance, northern anchovy and Pacific herring. Less is known about the species’ habitat requirements at sea, both during the breeding season and outside of it. Commercial fishing using gillnets can result in thousands of murrelets and other seabirds becoming entangled and drowning. Nests average about 4.2 inches along the length of the branch and 3.7 inches wide, with the interior about 1.5 inches deep. The Marbled Murrelet’s nesting habits remained a mystery until the late 20th century. However, they also forage far as far as 180 miles offshore at times, at least in the Gulf of Alaska. Males and females have sooty-brown upperparts with dark bars. Pairs often chase each other in flight during the breeding season, even diving into the sea while still flying—and continuing the pursuit underwater. Marbled Murrelet (Brachyramphus marmoratus), version 2.0. Dives generally last less than a minute, and are fairly shallow. Pairs appear to forage together, staying in contact with calls. Registered charitable number: 11914 9797 RR0001. Spills may also harm the murrelets’ prey species. Back to top. Alfred A. Knopf, New York, NY, USA. Marbled Murrelets often feed near shorelines, especially where tides or river currents concentrate prey. Marbled Murrelets eat mostly small fish and zooplankton, which they capture underwater with the bill, usually not far from land. Marbled Murrelets also court at sea in groups at this time. January 2020: Conservationists respond to lawsuits by timber industry with suit calling for management of Washington’s state forests to benefit “all the people” Very few humans have observed Marbled Murrelets at the nest, but the birds have been seen making close chases through the forest, calling, diving steeply, and making loud wing noises. (2014). Their prey may be concentrated by tides, upwellings, rip currents, river outflow, or other features of the marine environment, and large numbers of murrelets may gather at any time of year where food is plentiful. Murrelets can live as long as 25 years. A. and A. S. Love. Most nests have been found in large trees in old-growth forest, a few in rocky slopes. In addition to fish, they eat small shrimp such as northern prawn and squid such as opalescent inshore squid. Spills may also harm the murrelets’ prey species. Covered in down, can walk, but stays in nest. Washington, DC, USA. Ideal nesting habitat has a partly open canopy, which probably facilitates access to the nest. Sibley, D. A. The main sensitivities of marbled murrelets to climate change will likely be due to potential changes in prey availability and habitat. It is unclear whether these are territorial flights or social displays, since up to 12 birds may be involved. Less commonly, they make ground nests in a depression in a rocky talus slope, boulder field, or similar area, sometimes on moss, matted vegetation, or beneath taller vegetation such as alders. Winter adults have brownish-gray upperparts and white scapulars. Displaying birds (likely males) raise the wings above the back in a V-shape while swimming, giving an odd-sounding, whiny call. The Marbled Murrelet was listed by the US Fish and Wildlife Service as threatened in 1992, and was listed as threatened by the Washington State Department of Fish and Wildlife in 1993. The Cornell Lab will send you updates about birds, birding, and opportunities to help bird conservation. Murrelets spend most of their lives in the ocean, but come inland to nest. Logging and development of forested nesting habitat have been extensive, and large portions of this species’ nesting grounds have been cut already. Murrelets hunt and fly at night to avoid leading predators to the nest. Logging poses a significant threat to the species’ survival, both because of the birds’ reliance on old-growth trees and because forests become fragmented, exposing the birds to greater risk of predation.