246 Div. 1. VERTEBRATE ANBIALS.— AVES. Class 2. 



From the Gulls nave been very properlj' separated 



The Skuas (Lestris, Illiger), — 

 The membranous nostrils of Avhich, larger than in the preceding, open nearer to the point and edge of 

 the beak ; the tail also is pointed, [and they have great coeca]. They eagerly pursue the smaller 

 Gulls to rob them of their food, and, as has been said, to devour their excrement ; [the truth being, 

 that they cause them to disgorge, whereupon they seize the food before it reaches the water, being 

 endowed with uncommon power of flight] : hence their name, [Lesfris, or robber. 



Four species occur on the British shores, successively smaller, with the middle tail-feathers prolonged in the 

 same ratio. The largest {L. cataractes), nearly the size of the Great Black-backed Gull, has deep brown plumoge, 

 with the middle tail-feathers but slightly elongated. It breeds on certain of the northern Scottish isles, high 

 upon the mountains, defending its nest with extraordinary spirit and intrepidity, and furiously driving off Eagles 

 from the vicinity, for which reason it is protected by the inhabitants, as a guard to their flocks. The Pomarine 

 Skua (L. pomarinus) is smaller, and though generally exceedingly rare, makes its apearance in certain seasons in 

 considerable numbers, as in the instance of November, 1837. L. Richardsonii is the next in size, which is common 

 about the northern Scottish isles ; and L. parasiticus, the smallest, which belongs more properly to America, has 

 exceedingly long middle tail-feathers. The females of these birds are larger than the males, which is the reverse 

 of what is observable in the Gulls ; and they lay but two eggs, of a dark colour]. 



The Terns {Sterna, Linn.) — 

 Are termed Sea-sivallous, from their extremely long and pointed wings, their forked tail, and short legs, 

 which induce a port and flight analogous to those of the Swallows, [the true Terns, however, ivinnowing 

 more in the manner of the Gulls]. Their beak is straight, pointed, and compressed, without 

 curvature or projection ; having the nostrils near its base, oblong, and pierced quite through. The 

 membranes which connect their toes are deeply emarginated, and they swim little, [if at all]. They 

 fly in every direction and with great rapidity, uttering loud cries, and skilfully raising from the surface 

 of the water mollusks and small fishes, upon which they feed, [and to obtain which they often plunge]. 

 They also penetrate to the lakes and rivers of the interior. [Tlieir anatomy precisely accords with that 

 of the Gulls, as do also the character of their plumage, their seasonal and progressive changes, mode of 

 propagation, eggs, &c. 



The British species fall into two principal groups ; the majority having the same black calotte in spring as the 

 Xema Gulls. The commonest (*7. hirundo) has an ashy mantle, red feet, and the bill red with a black tip. The 

 Arctic Tern (St. arctica), common along our northern coasts, is rather smaller, with shorter legs, and under- 

 parts tinged with ash-colour. The Little Tern (St. minuta) is distinguished by its very inferior size, and white 

 forehead. The Sandwich T. (St. cantiaca and Boi/sii) is larger than any of the foregoing, with black feet, and 

 often a tint of roseate on the breast. In the Roseate T. (<S/. DougalU), the same tinge is brighter, and the feet 

 are orange. The Gull-billed T. (.S7. anglica) has the bill prominent at the symphisis, as in the Gulls; but not- 

 withstanding its received systematic name, is extremely rare in Britain. The Caspian T. (St. caspia), occasionally 

 met with in the Channel, is very considerably larger than any of the others. The two last are principally marsh. 

 Terns ; and the most characteristic of these is the Black Tern (St. nigra), with tail less deeply forked than in 

 the others, membranes of the feet more reduced, and smaller bill, which subsists chiefly on insects taken on the 

 wing, and flies more like a Swallow. There are numerous others.] 



We might distinguish from the other Terns, 



The Noddies {Megalopterus, Boie), — 

 The tail of which is not forked, [but the reverse,] and even with the wings ; and the bill has a slight 

 salient angle, the first indication of that in the Gulls ; [whilst the character of the plumage resem- 

 bles that of a Petrel, and the feathers are not continued forward to the nostrils]. We only know 

 of one, — 



The Black Noddy (Sterna sintida, Lin.).— Brown black, the front of the head whitish. It is well known to 

 Beamen for the stupidity with which it throws itself on vessels [and allows itself to be taken. Is one of the most 

 widely distributed of birds ; and has occurred on the Irish coast. M. Audubon found its nests in vast numbers, 

 placed upon bushes, in an island uninhabited by Man]. 



The Skimmers {Rhyncops, Linn.)— 

 Resemble the Terns by their short feet, long wings, and forked tail ; but are distinguished from all 

 other birds by their extraordinary bill, the upper mandible of which is shorter than the other, both 

 being flattened into simple [vertical] lamina;, which meet without clasping. Their only mode of 

 feeding is by skimming their aliment from the surface of the water with the lower mandible as 

 they fly. 



