SKIMMERS—PETRELS 333 



try to cover it with her body, and frequently succeeds in rearing a nestling in such 

 a precarious position that special precautions are necessary in order to prevent its 

 falling to the ground. 



A small group of birds included in the tern family take their 

 name of skimmers from the remarkable and unique conformation of 

 their beaks, which are nearly as compressed as knife-blades, with the lower half 

 projecting considerably beyond the upper one. Nocturnal in their habits, these 

 birds pass the day reposing quietly in undisturbed situations, but rouse themselves 

 towards evening, when they take to their wings and skiui the surface of the sea so 

 closely that they are enabled to sink the long lower half of the beak at intervals 

 into the water and thus to scoop up and secure the small fishes and crustaceans 

 which constitute their chief food. Skimmers, which range over the warmer parts 

 of Asia, Africa, and America, and are represented by five species, not only frequent 

 the shores of the sea and lagoons, but likewise resort to the banks of the larger- 

 rivers. The African scarlet-beaked species (Rhynchops flavirostris) is found, for 

 instance, alike on the shores of the Red Sea and on the banks of the Nile, ranging 

 over the whole of the coasts of the African continent with the exception of the 

 extreme north and south. This bird, which may be recognised by its red feet and a 

 beak vermilion for the greater part of its length but tipped with bright yellow, is 

 dark brown above, with the crown and sides of the head, the neck, and the under- 

 pays white. In India and Lower Burma this species is replaced by the yellow- 

 beaked R. albicollis, while in North and Central America the genus is represented 

 by the pied R. niger. 



Omitting mention of the gulls of the Indo-Pacific, which present 

 little of special interest, reference may be made to the black petrel 

 (Ptiffinus nativitatis), which ranges from Christmas Island, in the Pacific, to the 

 islands of the Phoenix group, on account of being one of several species which 

 burrow in loose, sandy soil to such an extent as frequently to make walking on 

 the shore a matter of extreme difficulty, as the thin layer of sand above the bur- 

 rows of the birds breaks in with every footstep. During the day these birds 

 remain in their subterranean dwellings, but at night they come forth, and utter 

 cries that sound like most melancholy wailings, although the members of each pair 

 sit side by side with an air of the most perfect content for hours at a stretch, 

 From time to time one will gently scratch the plumage of its partner's neck, while 

 both bill and coo like a couple of turtle-doves. Despite their apparent gentleness, 

 these petrels should, however, be approached with caution, as a single bite from 

 their pointed and crooked beaks is sufficient to produce a painful wound. A second 

 species, the blue petrel (P. hypoleucus), is remarkable for the regularity with which 

 it arrives at its breeding-places in the Pacific. On Laysan Island, for instance, 

 where the black petrel also breeds, the blue species always makes its appearance 

 between the 15th and the 18th of August. On arrival, the birds immediately 

 proceed to reoccupy their burrows, when the first task is to remove with their feet 

 the loose sand by which the entrances are blocked, this being generally performed 

 by moonlight. Shortly afterwards the real business of breeding commences, the 

 birds uttering throughout that season a peculiar kind of cooing cry, said to be 

 somewhat intermediate between the mewing of a cat and the crying of a child. 



