MUTTON BIRDS

Bay of Plenty Beacon, Volume 2, Issue 234, 6 November 1940, Page 3

MUTTON BIRDS

THEIR ARDUOUS LIFE By Rosaline Redwood in "Forest and Bird" In September they come— thousands of dusky-winged mutton birds, flying in mass formation like a black cloud suspended between heaven and earth. From distant Northern Asiatic shores they make their graceful flight, covering an almost incredible distance, to New Zealand's Mutton Bird Islands, a straggly, scattered formation of bush-clad islands lying off the coast of Stewart Island and the Bay of Plenty. When the iong migratory trip is almost over and the islands come in sight, some uncanny instinct guides them to their old nesting ground, where year after year the same birds and their families nest. The flocks wheel and scream in winged fixcile'mcnt, and when each bird 5s above the right area of land it closes its dusky wings and simply drops to earth.. This is certainly a strange method of landing. Some birds are killed by the 'fall, while the others lie for a moment as if stunned, then scuttle down their emptj r burrows. Strange Instinct. It is stated that the birds Ic-naw the Burrows which they occupied the previous year, and those they commence to clean out, preparatory to laying. ■ The burrows, which extend usually a few feet into the spongy ground, of the islands, arcso numerous that they fairly honeycomb the suruface in many places. It may be necessary for the younger birds to make fresh burrows, but, whatever the case may l be, both male and female birds share in the .labour,, working tirelessly without' thought of food until the task is accomplished. Leaves of the mutton bird tree are used to line the nest.

• Following th;j maling season, each female lays its one large, white egg The common belief is that all birds oix the same day, the 25th November, but more recent investigations have proved that eggs are deposited during the months of November, December and even later. A Solitary Egg. When the 'young one is hatched the parents leave before daybreak in search of food, returning after dusk. If ~bv chance an adult bi'rd is delayed in leaving in the eaii.v hours, it will • remain in its burrow all day rather than venture out in broad daylight. The. birds leave their islands in mass formation, fish ing in flocks, sometimes many miles from land. It is fascinating to watch these dense black clouds ol birds. The leaders of the flock swoop gracefully ahead of shoals of small fish, heading them off,-, and then diving commences. ' Although the mutton bird is practically helpless land, it is a strong swimmer and fast flier, and small fish fall an easy prey to its sharp beak. All day the birds gorge on and at dusk bear down on their home islands again, the noise of thousands of wings being deafening. Feeding the Young. There is great excitement in the burrows.. The young one pushes its beak inside that of the parent, and the partly' digested bits of fish are vomited up. On this fare the young one soon becomes very 'fat,, and by April is often larger and fatter than its parents. In appearance ; .t resembles a soft grey fluffy ball. HoAvever, the Maori button birders arc not deceived by the young bird's apparent softness, for they wear protection on their hands and arms before reaching into the burrows. The bird lias a sharp beak and can also use its feet to advantage, and as the scratches it inflicts often fester badly,, the natives take ne-

eessary precautions. About Maj- some of tlie old birds leave, but a few always remain liehind for another month or so to guide the numerous young ones which escape the mutton birders, back to the place yhithcr they and their ancestors have gone for centuries. In the meantime the young birds are gathering strength for their first long flight. The oil' which is secreted in their crops becomes stronger, and is the main source of' nourishment on which they must rely. With the parents gone and no food supply available, the chicks live 011 their store of fat. They become thinner and more vigorous, and adult plumage appears. At night they flop out of their burrows and lest their wings awkwardly, flapping them aimkssiy. The Great Migration. And then the great day arrives when they congregate 011 suitable ledges of rocks from which thev arable to leave with ease, and the {Continued at foot of nest column) J

first flight lasts until the youngj wings arc tired, "when the bird comcs to rest on the water. After a short spell off it goes again, this time for a longer flight—and so on until it reaches its distant destination. The mollyhawk and other vultures of the deep know exactly when tlie mutton birds "will leave their islands, and they come from .far and wide to gather in the locality of the Mutton Bird islands, there to wait for the prey that is theirs. Many birds are drowned each year, and some are blown out .of their course by string winds and left to perish, but it is certain from the number that return that most of them reach their migratory. land safely. Such is the anions life of one of • i>e inrst faseina[ ijig and remarkable :• X".'w Zealand's nrgratory birds.