[Case 44. | 
[Case 45.] 
a 
72 BIRD GALLERY. 
intertropical oceans, and in outward appearance, as well asin 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. Puarrnontips. Tropic-Birps. 
Only Six species of Tropie- or Boatswain-Bird (Phaéthon) (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 difficulty 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, and the single 
mottled purplish-brown egg is generally laid in a hole or crevice of the 
cliff, 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. fulvus) (820) from the 
Indian Ocean is another remarkable form, 
Order XX. CATHARTIFORMES. 
Family Carmarrima., Turkny-VuLrures. 
Tnese aberrant Birds of Prey are found only in America. In their 
habits they closely resemble the Vultures of the Old World, but they 
differ 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 (p. 208, fig. ix.). 
