220 SEA-BIRDS 



unguarded nests or from boobies returning with material in their bills. 

 The best frigate-nests are nevertheless very poor, but as the season 

 advances they become soHdified with excrement. The male takes a 

 large part in incubation; his ballooning of the gular pouch ceases 

 then. They are tame when unmolested at the nest, and are heavy 

 sleepers at night. Buller (1905, p. 50) quotes the case of frigate-birds 

 being so tamed by feeding that they were used to carry messages be- 

 tween two islands 100 kilometres apart; the birds became accustomed 

 to being fed at perches placed for them outside human dwelHngs in 

 a number of Samoan islands. They were easily handled at night when 

 it was desired to affix or remove the message contained in a reed 

 cyHnder fastened to the wing; and since these birds never enter the 

 water the cylinder would be safe from destruction by that element. 



That curious appearance of harmony at the breeding ground 

 between parasite and host often seen in other species exists between 

 frigate-bird and booby nesting in the same tree colony. The booby 

 may be relentlessly pursued over the sea, but enmity (except for stick- 

 stealing) ends on the land. The frigate chicks may be seen in nests 

 close to those containing booby youngsters, both species lying fast 

 asleep at noon with downy heads drooping over the side dejectedly, 

 the new quillshafts, surrounded by powerful young muscles, charged 

 with blood to feed the developing wings. 



Two more remarkably beautiful tropical wanderers of the Pelecani- 

 form order breed in the warm North Atlantic : the red-billed {Phaethon 

 aethereus) and the white-tailed {P. lepturus) tropic-birds. Boatswain- 

 bird is a title earned from the shrill whistle, the long pointed tail 

 resembling a marlin spike, and the habit of coming up to inspect a 

 passing ship, of these white sea-birds — which cross and recross the 

 ocean desert of the Sargasso Sea, with swift dove-like ffight, at points 

 farthest from the mainland in the whole North Atlantic. At Ber- 

 muda the colony of 2,000 pairs of P. lepturus was counted and studied 

 by Gross (19 12) and Plath (1914). The one chocolate-splashed tgg 

 is laid in a hole or burrow in the cliff. Features of the breeding 

 biology resemble those of the petrels: the clumsy shuffling on land of 

 these wonderful ffiers, the hole-nesting, incubation by both sexes, the 

 long fledging period, the desertion of the young. Pairing takes place 

 at the nest. After twenty-eight days or more of incubation the feeble 

 blind chick hatches. It opens its eyes in a few days, and grows rapidly 

 on a diet of fish and squids. The adults make two foraging journeys 

 each day: at dawn, returning in the morning; and some hours before 



