Ocean birds are readily divisible into four families. The first is made up of the 25 Storm-Petrels; the second of the 75 Petrels, Shearwaters, Fulmars, and Dove-Petrels; the third family comprises only the three small southern Diving-Petrels; while the fourth contains the nineteen noble Albatrosses.
Though Storm-Petrels and Petrels of various kinds may be seen in the Northern Hemisphere, yet the Southern Hemisphere, with its enormous expanse of water, is the headquarters of these birds.
The dainty, tiny Storm-Petrels, fearlessly tripping over the mountain billows in times of great danger to the sailor, were considered birds of ill-omen. Their peculiar flight possibly helped this idea. Gould closely studied them and other ocean birds during his voyages on sailing ships. He describes them as "fluttering over the glassy surface of the ocean during calms with an easy butterfly-like motion of the wings, and buffeting and breasting with equal vigor the crests of the loftiest waves of the storm; at one moment descending into their deep troughs, and, at the next, rising with the utmost alertness to their highest point, apparently from an impulse communicated as much by striking the surface of the water with its webbed feet as by the action of the wings."
This habit of "walking" on the sea is said to be responsible for the name "Petrel," which is associated with Saint Peter, who, of old, walked on the waters. Sailors call them Mother Carey's Chickens.
The largest Australian Storm-Petrel is the Whitefaced Storm-Petrel, whose scientific name, Pelagodroma, means "open sea wanderer." It has been recorded even from the North Atlantic and Britain. Many thousands of these birds still nest on Mud Island, a sandbank just inside Port Phillip Heads. The presence there of a true ocean wanderer is a valuable piece of evidence to support the geographer in his claim that Port Phillip Bay once had a wide opening, which has been almost closed by the drift of sand across its mouth. The Storm-Petrels have probably nested there for many, many centuries. Long may they continue to do so! They hurt no one, and they are a feature of interest to all interested in the flora and fauna of Australia, and to natural history students and Nature-lovers in general.
The Shackleton expedition met the Wilson (Yellow-webbed) Storm-Petrel, in considerable numbers, far south. Two specimens were presented by Lieutenant Shackleton to the National Museum, Melbourne. However, recently our Museum received, through the agency of two schoolboys, a specimen that is valued even more highly, for it is Australian.
The boys, on their way to the Marshaltown State School (Mr. H. B. Williamson, H.T.), found a bird near a fence about nine miles inland. It had evidently been killed by flying into the fence in the dark. Using the Bird-List, the boys discovered that it was a Yellow-webbed Storm-Petrel, a truly pelagic bird, as its name, Oceanites oceanicus indicates. Mr. Williamson, to show that the List was of assistance, even to boys, in identifying birds they had never heard of before, left the bird at the Continuation School, Geelong. Here it was recognized as a valuable specimen, and was at once sent to Mr. Kershaw, curator of the National Museum. It is now in the Australian collection.
The true Petrels are very numerous in kinds and individuals. Darwin thought that the most numerous of birds was a Petrel. One of great interest is the "Mutton-Bird," or Short-tailed Petrel. This romantic bird breeds by the million on Cape Woolamai and other places about Bass Strait.
Just as the mallee farmer is dependent on his annual wheat harvest, so the remarkable colony of people living on Cape Barren Island is entirely dependent on the annual Mutton-Bird harvest. They claim to take about a million and a half birds each year. The number is probably much exaggerated, for Littler, in his valuable Birds of Tasmania, gives the number as 555,000 for 1909, valued at about £4000. Bass and Flinders were glad to replenish their stores with young Mutton-Birds. Flinders calculated that one flock of these birds he met in Bass Strait contained 132,000,000 birds. They lay but one egg, so one would expect the Petrel to be long-lived. We found a closely-similar bird nesting on Mast Head Island, Capricorn Group.