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Godman Frederick du C. A Monograph of the Petrels (order Tubinares). Part III

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Godman Frederick du C. A Monograph of the Petrels (order Tubinares). Part III
London: Witherby & Co, 1908. — 231 p.
Petrels apparently belong to an ancient race of birds, as their remains have been found in a fossil state in various parts of the world, though mostly in superficial deposits; Diomedea anglica, however, is known from the Red Crag of Norfolk (Lydekker, Cat. Fossil Birds in Brit. Mus.).
The Order Tubinares embraces Families differing in external appearance to an extraordinary degree, and varying in size from the tiny Storm Petrel to that of the Wandering Albatros. The greater number of the species are of powerful flight, fitted to combat oceanic storms, in which the larger ones in particular appear to delight.
The members of the Family Pelecanoididae, however, which are peculiar to the southern oceans, and resemble the Little Auk of the northern seas both in appearance and habit, frequent sheltered bays in preference to open waters, and procure their food by diving, for which they are specially adapted. Notwithstanding these wide differences, Petrels may at once be distinguished from all other birds by their prominent tubular nostrils, and by their bills, which consist of several horny pieces separated by deep grooves.
Petrels are dispersed throughout all the oceans of the world, penetrating to the Ice Barrier at both poles, though they are probably more numerous in the southern than in the northern hemisphere. They are purely oceanic wanderers, and unless driven ashore by storms, seldom, if ever, come to land except for the purpose of breeding, and then they invariably select unfrequented rocks and islands difficult of access. All the smaller species nest in burrows in the ground, or in the clefts of rocks, and are more or less crepuscular in habit.
Considering the vast number of these birds inhabiting the seas, it seems remarkable at first sight that so much difficulty is experienced by our Museums in obtaining examples, but this, of course, is due to their mode of life, and the great difficulty in securing specimens at sea. It must also be remembered that many species resemble each other very closely and the slight differences between them are not easily identified from the deck of a passing ship, even by a competent observer, hence much that has been written on the occurrence of certain birds in stated localities must be received with caution.
With regard to the plumage, much more information is still required as to the various stages through which the birds pass before reaching the adult. Some doubtless assume the mature plumage as soon as they are fully grown, while others, such as certain of the Albatroses, take years before they acquire their full dress. Again, much remains to be learned respecting the colour of the legs and bill, which in some species appears brighter during the breeding season, but as these parts change colour in the dry skin, accurate information on these points can only be obtained from living or freshly killed specimens.
A marked peculiarity of these birds is the habit of ejecting a foetid fluid from their nostrils, which is apparently used by certain species as a means of defence, when it can be discharged to a distance of three feet at the approach of any intruder. Owing to the introduction of the mongoose and other small carnivorous mammals into their breeding haunts, some species, such as Estrelata jamaicensis and newelli, have already been completely exterminated, and others appear to be in danger of extinction. The habit of some species of nesting in immense colonies is also leading to similar results, as, for purposes of food, the eggs are taken and young frequently robbed and killed in such countless thousands that extermination becomes only a matter of time.
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