72 BIKD GALLERY. 



intertropical oceansj and in outward appearance, as well as in habits, 

 resemble some of the lower Birds of Prey, such as Kites. Their strongly 

 hooked bill, large gular pouch, very short legs feathered to the toes 

 which are only united by very small webs, immensely long wings, and 

 deeply forked tail, are all striking characters. Their powers of flight 

 are perhaps superior to those of any other bird, and they employ their 

 great speed to overtake and rob the smaller sea-birds, harassing them 

 till they drop or disgorge their prey, which is dexterously caught in 

 mid-air and swallowed. They also kill and devour numbers of young 

 birds, even those of their own species. The nest is made of sticks and 

 placed in trees or bushes, sometimes on the bare rocks. The single 

 egg is very similar in appearance to that laid by the Cormorant, and 

 both sexes take part in the duties of incubation. 



Family V. Phaethontid.e. Tropic-Birds. 



[Case 44.] Only six species of Tropic- or Boatswain-Bird {Phaethon) (818-822) 

 comprise this small family and, as their name implies, inhabit the inter- 

 tropical oceans. They are easily distinguished from the other Pelican- 

 like Birds by their sharp-pointed bill serrated along the edges, and by 

 the middle pair of tail-feathers being greatly elongate and attenuated. 

 The legs are so very short that the gait on land is awkward and 

 shuffling, and they can only rise with difiBculty from the level ground. 

 Tropic-Birds are often met with hundreds of miles from land, and their 

 rapid flight is performed by quick pulsations of the wings. They 

 will often follow vessels for hours, sometimes soaring high overhead in 

 circles or settling on the rigging. No nest is made, aad the single 

 mottled purplish-brown egg is generally laid in a hole or crevice of the 

 clifl^, though sometimes a hollow tree is resorted to. Of the three 

 species exhibited the most striking is perhaps the Red-tailed Tropic- 

 Bird (P. rubricauda) (818) with its silver- white plumage and scarlet 

 streamers, while the Fulvous Tropic-Bird (P. fulviis) (820) from the 

 Indian Ocean is another remarkable form. 



Order XX. CATHARTIDIFORMES. 



Family Cathartid^. Turkey-Vultures. 



[Ca=e 45,] These aberrant Birds of Prey are found only in America. In their 

 habits they closely resemble the Vultures of the Old World, but they 

 difPer so much from the true Accipitrine Birds in their anatomy and 

 osteology that they are now placed in a separate order. We may 

 specially mention the peculiarity of the nostrils, which are pervious and 

 not divided from one another by a bony septum or partition. 



