AVES. 389 
follow ships for immense distances, for the purpose of picking up such arti- 
cles suitable for their food as may be thrown overboard. The cape pigeon, 
Procellaria capensis (pl. 91, fig. 11), and the stormy petrel (Thalassidroma 
pelagica), are common species. 
Fam. 5. Larmwa. This extensive family embraces all the common and 
generally handsome sea-birds known by the names of gulls and terns. They 
are natives of the sea-shores of all countries. 
Sub-fam. 1. Larine, or Gulls. Bill rather long, straight, curved at the 
tip, which is acute ; wings long, pointed; tail moderate ; tarsi short, strong ; 
feet moderate, fully webbed. Size various; colors mostly white, and light 
cinereous. 
Nearly fifty species of these birds are scattered over the marine portions 
of the world, sometimes, during winter, being found in the marshes or on 
the borders of rivers, but returning to the sea coast during summer. They 
are generally gracefully formed birds, with pure white or cinereous plumage. 
The black-headed gull (Larus atricilla), the kittiwake (L. rissa), the ivory 
gull, L. eburneus (pl. 91, fig. 5), a beautiful pure white species, the burgo- 
master (L. glaucus), the black-backed gull or saddle-back (L. marinus), and 
the herring gull, L. argentatus (pl. 92, fig. 11), are the principal species of 
the American sea-coasts, and are also found on those of Europe. 
Sub-fam. 2. Sternine, or Terns. Bill rather long, slender, straight, sharp ; 
wings very long, pointed; tail long, generally forked ; tarsi and feet short ; 
Size various ; color mostly white. 
These handsome birds, known on the Atlantic coasts of the United States 
by the name of sea-swallows, frequent all the sea-coasts of the world. They 
are continually on the wing, and their flight is frequently elevated, but at 
other times near the surface, and of long continuance. When seeking their 
food, which consists of small marine animals, they generally perform large 
circles, and, upon discerning a suitable object, suddenly dart upon it. At 
other times they sweep over the surface of the water in the manner of 
swallows, seizing with their bills any floating objects. The great sea swal- 
low, Sterna hirundo (pl. 92, fig. 12), the little tern (S. minuta), and, the sooty 
tern, S. nigra (pl. 91, fig. 4), are common species. 
There are nearly one hundred species of terns. 
Fam. 6. Perecanip®. Contains the pelicans, cormorants, tropic birds, 
and some others. They are generally large and powerful birds, and inhabit 
principally the southern hemisphere. 
Sub-fam. 1. Phetonine, or Tropic Birds. Bill rather long, broad at base ; 
wings long, pointed; tail moderate, two middle feathers lengthened ; tarsi 
and feet short. Size rather small; color white. 
Four or five species of these birds inhabit the southern seas, and are 
usually observed at a considerable distance from land, skimming over the 
surface of the water, seizing such fishes and other marine animals as 
approach the surface. They are the especial enemies of the flying fish, 
and are said to rear their young in hollow trees or in the fissures of rocks. 
The white tropic bird, Pheton ethereus (pl. 92, fig. 4), is a good example 
of these birds. | 
ICONOGRAPHIC ENCYCLOP £DIA.— VOL. II. 38 593 
