Scientific name: Synthliboramphus wumizusume
Japanese: Kanmuri Umisuzme (Crested Sea-Sparrow)
Russian: Khokhlatyi Starik (Crested Ancient Murrelet)

Although it was possibly more widespread in the China Sea toward Korea, the Japanese Murrelet probably has never been a populous species. Today it is perhaps the rarest of all alcids and may be on the verge of extinction. In southern Japan it is now restricted to less than a dozen small islands between 32° and 34° north latitude. (Reference to the map in the Appendix locates and names the known breeding colonies.) Birojima is probably the breeding site for possibly 1500 pairs. Yukio Higuchi wrote in a personal letter that at least two colonies listed in The Ornithological Society of Japan's Checklist of Japanese Birds, no longer exist, and several others are now doubtful breeding locations. It is apparent, then, that the range of this species is rapidly shrinking.

On the Mimiana Islands, the population was about 150-200 individuals in 1974, and in the same year a colony of about four hundred birds bred on Koyajima. According to Yukio Higuchi, in the same communication mentioned above, other colonies are smaller.

Careful search in 1976 of 410 square meters of habitat on Koyajima revealed that the breeding population was 28 percent less than it was in 1974. ⁴⁵⁰ If we assume that all eleven known locations each had four hundred birds, then the total population would be a meager 4,400 birds. The real numbers are likely to be less than half of this figure.

It is interesting to note that the Craveri's Murrelet which breeds in the same latitude on the eastern side of the Pacific also has very low population figures. These two species extend to the southern limits of the auk family, and may be restricted in population size by the lower availability of food in warmer seas. Breeding habitat on Koyajima includes grassy areas along with brushy sedges thirty to fifty centimeters tall. Scattered rocks, overhanging matted grass, and sedges provide cavities and eaves under which the birds nest. On these islands, the smaller spaces are occupied by the storm petrel (Oceanodroma monorhis ). The nests of the Japanese Murrelet are found between 15 and 60 meters above the sea and are usually lined with a thin mat of grasses. On the Mimiana Islands, the birds nest on the forest floor in cavities between the roots of oak trees or in burrows. The burrows may be 50 to 100 centimeters deep and in the wooded area as many as five nesting holes per square meter have been noted. ²⁷³ On Sanbondake Reef in 1953, Jack Moyer counted seven nests under one large boulder, indicating a colonial nesting pattern. ⁴⁰¹

Like other species of murrelet, the Japanese Murrelet is nocturnal in its breeding habits. It comes to land in the dark where it exchanges nesting duties, disputes territory, and engages in noisy vocalizing. Little is known about its behavior otherwise. Except when incubating or brooding, the bird spends the daylight hours at sea. When disturbed on the sea it raises its head high and utters chirps in a type of warning or aggressive display. When mated birds become separated at sea, they also locate each other by calling.

The Japanese Murrelet is described as quite tame, allowing a boat to approach to within fifteen meters or less before it dives. It seldom takes to the air, doing so only when a boat approaches too closely. Even then, it may fly only fifty or sixty meters to splash into the water again, submerging immediately.

An adult in nuptial plumage bears a posteriorly-pointed tuft on the frontal part of the head. This tuft consists of ten to twelve tapering plumes about 6 to 7 centimeters long. The nape is white, forming an almost complete collar which extends forward above the eye. Its black cap and tuft provide the bird with well-dressed, distinctive features. Both sexes are alike, and the juvenile similar in color to the adult winter plumage.

Crested Sea-sparrows, as they are locally known, lay two eggs, yellowish-brown or whitish in color, and spotted or flecked with various shades of gray and brown. The egg tends to be smaller than those of the Ancient Murrelet. Three eggs weighed by Higuchi ranged from 41.3 to 48.5 grams.

The breeding season begins in February, and by May, after incubating for thirty-two to thirty-five days, the eggs hatch and the two or three-day-old chicks leave with their parents for the sea. In this respect, they show their close relationship to the Ancient, Craveri's and Xantus' Murrelets.

The Japanese Murrelets may be seen at sea within its breeding range almost all year long. However it tends to be difficult to find between October and early February.

Stomach contents give some clue to the bird's feeding habits. Small fish, mollusks, and occasionally crab larva, have been found in stomachs of birds near Sanbondake Reef. The mollusks indicate that the Japanese Murrelet feeds near the bottom and is probably littoral in its foraging habits, at least in early April. ⁴⁰¹

Birds of prey, such as falcons and owls are known to kill Japanese Murrelets as indicated by the remains found at the breeding sites. Crows are known to prey upon the eggs. Accidental burning of the vegetation may have contributed to the decline on at least one island, and practice bombing prior to 1953 depleted the numbers on Sanbondake Reef, a practice which was stopped when the danger to this beautiful bird was indicated to the the authorities. Change in habitat because of erosion and sea pollution could also contribute to the gradual extinction of the Crested Sea-sparrow, factors which we may hopefully delay by creating more suitable nesting sites and by scrupulously protecting its nesting areas during the breeding season.