The identification of this species is confounded by the similarity of its close relatives Kittlitz’s Murrelet and, especially, Long-billed Murrelet. Structurally, Marbled Murrelet is shorter-billed than Long-billed Murrelet but noticeably longer-billed than Kittlitz’s Murrelet, but these structural differences may not always be apparent on distant birds. Breeding-plumaged Marbled Murrelet can usually be distinguished from breeding-plumaged Long-billed Murrelet by its darker throat (the chin and throat of Long-billed Murrelet are usually extensively mottled with white in breeding plumage and contrast strongly with the rest of the dark brown head and neck). In addition, Long-billed Murrelet shows narrow white eye-arcs during the breeding season which are lacking in Marbled Murrelet (giving the latter an overall much darker facial pattern). Furthermore, the Long-billed Murrelet is a more uniformly brown bird that lacks the extensive rusty mottling and feather edgings on the upperparts that are present in Marbled Murrelet. In non-breeding plumage, the most characteristic difference between Marbled and Long-billed Murrelets is the entirely dark nape of the Long-billed Murrelet. In Marbled Murrelet, the white of the throat and foreneck wraps around the rear edge of the ear coverts and on to the side of the nape, nearly forming a white collar across the back of the head. In Long-billed Murrelet, however, the nape is entirely dark and the white on the head is confined to the chin and throat. In addition, Long-billed Murrelet retains white eye-arcs into the non-breeding plumage, which can help in distinguishing it from Marbled Murrelet (which lacks white eye-arcs).
Marbled Murrelet may also be confused with Kittlitz’s Murrelet, which occurs in B.C. only as a vagrant. It is quite different from Marbled Murrelet in all plumages, particularly in non-breeding plumage, but caution should nonetheless be taken when confronted with a potential Kittlitz’s Murrelet in B.C. During the breeding season, Kittlitz’s Murrelets are overall much paler than Marbled Murrelet. The breeding plumage is extensively buffy or golden-brown with dark mottling (giving the bird a ‘spangled’ appearance), and is very different from the dark, rusty-toned plumage of Marbled Murrelet. The pale colouration of Kittlitz’s Murrelet extends onto the entire head which, due to the lack of a dark cap (as is found in Marbled Murrelet), the dark eye stands out noticeably on the pale head. In flight, the white central belly and lower breast of Kittlitz’s Murrelet should be obvious (underparts of Marbled Murrelet usually extensively mottled with dark brown), contrasting with the mottled golden-brown sides and flanks. In non-breeding plumage, the head of Kittlitz’s Murrelet is primarily white, with black confined to the central crown, nape, and hindneck and extending onto the sides of the neck and sides of the breast as a partial (sometimes nearly complete) dark collar. Because of the extensively white face, the dark eye is isolated from the dark cap and is very prominent (in Marbled Murrelet, the dark eye is within the dark cap and is not obvious except at close range). Additionally, the upperparts of Kittlitz’s Murrelet are paler grey, unlike the dark slate-grey upperparts of Marbled Murrelet.
There are several other species that may be confused with Marbled Murrelet, but these species are all reasonably distinct and will only be briefly mentioned. Ancient Murrelet is found in many areas alongside Marbled Murrelet throughout the year and is the most likely confusion species. It is reminiscent on non-breeding Marbled Murrelet but is easily distinguished by its blackish face (black extending onto the ear coverts and chin) and paler grey upperparts that lack the white scapular patch. At close range, its short pale yellow bill can be seen; this is very different from the longer, more slender black bill of Marbled Murrelet. In flight, it is a chunkier species with slower wingbeats and often flies in small flocks (Marbled Murrelets usually seen singly or in pairs). Xantus’s Murrelet, which occurs as a rare vagrant on the outer coast, is similar to non-breeding Marbled Murrelet but lacks the white half-collar on the sides of the nape (white on the head confined to the throat and malar area). As well, it is wholly blackish above (lacks the white patch on the scapulars and white on the sides of the rump) and has entirely whitish (rather than dark grey-brown) underwings which are easily visible in flight.
Source: Sibley (2000)
| This species is relatively vocal for an alcid. The most commonly-heard call is a high-pitched, squealing, descending keeeer or klee-ee-eer, often given in series; this call can be heard from birds at sea, from individuals flying to and from nesting areas, and from birds at nesting sites. Also gives a high, clear quip. Source: Nelson (1997); Sibley (2000) |
Courtship
Courtship and pair formation occur at sea during the spring (occasionally in winter), often when one or both individuals are still in non-breeding plumage, as well as throughout the summer. A ‘Bill-Up’ display is often performed during this courtship period, in which the male and female swim side-by-side with their bills pointed up into the air, partially lift their breasts out of the water, and then swim rapidly forward together for as long as 30 seconds. Synchronous diving by the pair also occurs during courtship, with the birds returning together to the surface after only a few seconds underwater. At dawn, and immediately preceding the ‘Bill-Up’ display, one member of the pair often engages in a ‘V-Wing’ display in which the bird half-opens its wings (forming a ‘V’) and swims alongside its mate while uttering unique buzzing calls. Other displays associated with pair formation include aerial chases (often followed by one or both birds crashing into the water and subsequently diving) and vocalizing.
Nest
Nest building begins in early March, but later nests may be constructed as late as July. Many of the details of nest building remain poorly-known in this species, but it appears that both sexes participate in selection of the nest site. Except in northern portions of its range, where it often breeds in treeless coastal tundra, most nests are situated in trees. Tree nests are built on large-diameter limbs or other platforms (such as those created by unusual tree growth due to mistletoe infestation or other disease) in old-growth or very old second-growth coniferous trees. The nest is almost always placed atop a thick cushion of moss, usually within the top one-half to one-third of the tree canopy (nest height ranges from 7-75 m). It is usually concealed from above by overhanging branches and boughs, but is open on the sides and allows horizontal access by the incoming birds. Occasionally, nests are found on the ground amongst coastal talus or on ledges on cliff faces (rarely on the ground in forested habitats). The nest is ~15-26 cm wide and ~1-8 cm deep, and is often little more than a depression in a thick cushion of moss with a lining of finer materials. Tree nests are lined with moss, lichens, needles, or small twigs, but those on the ground (especially in talus) often include rocks, soil, or herbaceous vegetation.
Eggs
The breeding period of this species is rather prolonged, with individual pairs nesting asynchronously at any time between early spring and mid-summer. A single egg is laid between mid-April and late June or early July in B.C., and is incubated by both sexes for 27-30 days before hatching. The smooth, non-glossy to slightly glossy egg is pale olive-green to greenish-yellow with irregular brown, black, and purple spots (concentrated towards the larger end of the egg). Eggs are present in B.C. between mid-April and late July.
Young
The young are semi-precocial upon hatching. Nestlings are initially covered with buffy-yellow down, except for the belly which is covered with grey or buffy-grey down (darker on the sides and flanks), with dark brown or black spots on the head and upperparts; the spots on the head are concentrated in large patches. The bill is black and the legs and feet are dark grey. The young are brooded for only 1-3 days after hatching, but are fed by both parents for the entire nestling period (28-40 days). The young fledge in juvenal plumage and fly directly from the nest to the ocean (occasionally becoming stranded en route if they are unable to reach the ocean). They are fully independent once they reach the ocean and receive no further parental care. Newly-fledged young can occur on coastal waters on B.C. as late as October.
Source: Campbell et al. (1990b); Baicich and Harrison (1997); Nelson (1997)
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Although occasional individuals appear on coastal lakes during the breeding season (and will occasionally consume small freshwater fish), almost all foraging occurs on the ocean throughout the year. It feeds primarily on small schooling fish such as Pacific Sandlance, Pacific Herring, smelt, seapierch, and a variety of juvenile fish, particularly during the breeding season, with marine invertebrates such as crustaceans (euphasids, mysids, amphipods, etc.) becoming more important during the winter. Pacific Sandlance is the most important prey species in much of British Columbia. Most foraging occurs in relatively shallow waters or in deeper waters where there is significant upwelling or other strong currents (such as those from tidal rips). It usually forages alone or in pairs throughout the year, capturing its prey during relatively short (20-44 seconds) dives that can reach depths of 50-60 m. During the breeding season, large numbers of fish are captured during repeated dives and then carried inland to be fed to the nestlings.
Source: Nelson (1997)
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