Family LARIDAE. The Gulls. 



Ch. — Bill generally shorter than the head, straight at the base, and more or less curved at the end. Nostrils linear. Head 

 ovate ; neck short ; body rather full and compact ; wings long and pointed ; legs of moderate length, strong, and covered 

 anteriorly with transverse scales ; feet fully webbed, the hind toe small and elevated. 



Birds of this family frequent tlie shores of the ocean_, but often wander to great distances 

 from land ; they are incapable of diving, but swim buoyantly. Their food consists principally 

 of fish and Crustacea, but some of the larger species feed occasionally on the flesh of cetaceous 

 animals, and devour the young and eggs of some species of sea birds. 



The family of Laridae is divisable into four sub-families, with the following characters : 



Lestridinae. — Basal half of upper jaw with a horny covering, distinct from the tip, and 

 under which the nostrils open considerably beyond the middle of the bill . Bill abruptly and 

 much decurved at the tip. Tail cuneate. Body full, stout. 



Larinab. — Covering of the bill continuous. Anterior extremity of nostrils generally reaching 

 to the middle of the bill. Culmen considerably decurved towards the tip. Body robust. Tail 

 generally even. 



Sterninab. — Covering of bill continuous. Nostrils opening in the basal third of the bill. 

 Culmen gently curved to the tip of the lengthened and attenuated bill. Body rather slender. 

 Wing lengthened. Tail usually deeply forked. 



Ehtnchopinab. — Bill excessively compressed, like the blade of a knife. Lower jaw much 

 longer than the upper ; the point obtuse. Body slender ; tail forked. 



Sub-Family LESTRIDINAE.— T h e Skua Gulls; the Jagers. 



Ch. — Bill strong and much curved at the end, the base covered with a membranous cere. Wings lengthened. Tail cuneate, 

 with the two central feathers projecting. 



These hardy birds inhabit the high latitudes of both hemispheres. There are four Arctic 

 species found both in Europe and North America. They are piratical in their habits, appearing 

 to derive their subsistence mainly from the labors of others. They chase and harrass various 

 species of gulls, compelling them to disgorge a portion of their food, which they dart after and 

 seize before it reaches the water. 



Bonaparte, in his conspectus of Laridae, admits two genera of Lestridinae, with the following 

 characters : 



Stercorarius, Vieill. — ^Bill and feet robust. Tarsi shorter than middle toe. Median tail 

 feathers broadly rounded at tip ; not much longer than the others. Size large. Species ;S'. 

 catarractes, 



Lbstris, 111. — Bill and feet slender ; tarsus not longer than middle toe. Tail feathers much 

 elongated. Size moderate; ^t^qcxqs L.pomarinus, parasiticus, cepphus. 



I shall, however, consider both under a single genus, Stercorarius. 



