Ancient Murrelet (Synthliboramphus antiquus)

[order] CHARADRIIFORMES | [family] Alcidae | [latin] Synthliboramphus antiquus | [UK] Ancient Murrelet | [FR] Guillemot a cou blanc | [DE] Silberalk | [ES] Mergulo Antiguo | [NL] Zilveralk

Subspecies

Physical charateristics

A small, stocky bird, the Ancient Murrelet is slate-gray above, with gray and white sides and a white belly. The head is black, and the bill is pale. White on the throat extends back and up to the ears. During the breeding season, the throat is black, with a white band at the neck. The eyebrow is accented with white feathers at this time.

Listen to the sound of Ancient Murrelet

[audio:http://www.aviflevoland.nl/sounddb/A/Ancient Murrelet.mp3]

Copyright remark: Most sounds derived from xeno-canto

Range

Eurasia, North America : North Pacific coasts

Habitat

Ancient Murrelets spend most of the time on cold-water seas. They forage over the edge of the continental shelf, and also closer to shore, especially in areas where tidal currents bring food up to the surface. They nest on islands or inland in dense forests with thick moss but little underbrush.

Reproduction

In spring, Ancient Murrelets gather on their colonial breeding grounds. They spend their days at sea, and visit the breeding grounds by night. Early in the breeding season, males arrive after sunset each night and find a suitable perch from which to “sing” to potential mates-highly unusual behavior for a seabird. Once paired, the birds dig a burrow in soft soil, often among tree roots or in some other concealed area. The female lays two elongated, buff colored eggs, which are incubated by both parents for up to 33 days.
Once hatched, Ancient Murrelet chicks are fully feathered and able to move about almost immediately. They spend up to three days in the burrow without being fed. They are then coaxed out by the parents, and make their way to the sea by night. This seaward journey often takes place en masse, as many sets of chicks within the colony may depart for the sea simultaneously. The burrow is often high on a steep, densely forested coastal slope. From here, the tiny chicks undertake a long, dark, descending scramble to the crashing surf below. Once at sea, the chicks are able swimmers, and locate their respective parents via voice recognition. Once reunited, family groups move out to sea, where the parents feed the chicks for at least a month, at which point they are fully grown.

Feeding habits

Small fish, krill, and shrimp make up most of the Ancient Murrelet’s diet

Conservation

This species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
The breeding range of the Ancient Murrelet extends around the entire northern Pacific Rim, stretching from the Sea of Japan to British Columbia. In North America, its breeding range spans Alaska’s Aleutian Islands and southern mainland coast, as far south as Vancouver Island. In the Aleutians, the species can be locally common, breeding in over 50 locations. British Columbia, however, is home to at least half of the global population. In winter, the Ancient Murrelet can be found in coastal waters as far south as southern California. The Ancient Murrelet may be far more common in the North American portion of its range.

Migration

Post-breeding dispersal somewhat limited, some birds remaining within breeding range. Rapid exodus from N British Columbia Jul-Sept, with Marked S movement in Oct in both W and E Pacific, S to California (arrives late Oct) and to Japan and Korea (high numbers present Dec-Mar). Dispersal generally limited to short distances except in Sea of Okhotsk, where birds forced out by winter ice. Returns to breeding areas at least a month before laying begins. Details of winter distribution and movements are lacking throughout range.

Distribution map

download full text (pdf)

download full text (pdf)

download full text (pdf)

download full text (pdf)

download full text (pdf)

download full text (pdf)

download full text (pdf)

download full text (pdf)