534 THE FEAIIIERKU XlllBES. 



under mandible is more compressed than tlie upper, and very thin, both edges being us 

 sharp as a knife, and is almost an ineh longer than the upper mandible, which has a 

 narrow groove or channel into which the upper edge of the lower mandible shuts." 

 The male is about nineteen inches in length. The expanded wings measure twcntj'-four 

 inches. The female is smaller than the male. 



"Wilson thus describes their mode of taking food on the wing : — '' The sheerwater is 

 formed for skimming while on the win^, the surface of the sea for its food, which consists 

 of small fish, shrimps, young fry, whose natural haunts are near the shore and towards 

 the surface. That the lower mandible, when dipped into and cleaving the water, might 

 not retard the bird's way, it is thinned and sharpened like the blade of a knife ; the 

 upper mandible, being at such times elevated above the water, is curtailed in its length, 

 as being less necessary, but tapering gradually to a point, that on shutting it may suffer 

 no opposition. To prevent inconvenience from the rushing of the water, the mouth is 

 confined to the mere opening of the gullet, which indeed i^revents mastication taking 

 place there ; but the stomach or gizzard, to which this business is solely allotted, is of 

 uncommon hardness, strength, and muscularity, far surpassing in these respects any other 

 water-bird with which I am acquainted. To all these is added a vast expansion of wing- 

 to enable the bird to sail with sufficient celerity while dipping in the water. The general 

 proportion of the wing of our swiftest hawdis and swallows to their breadth is as one to 

 two ; but in the present case, as there is not only the resistance of the air, but also that 

 of the water to overcome, a still greater volume of wing is gi>en, the sheerwater 

 measuring nineteen inches in length, and upwards of forty-four in extent. In short, 

 wlioever has attentively examined this curious apparatus, and observed the possessor, 

 with his ample wings, long bending neck, and lower mandible occasionally dipped into 

 and ploughing the surface, and the facility with which ho procures his food, cannot but 

 consider it a mere playful amusement, when compared with the dashing immersions of 

 the tern, the gull, or the fish-hawk, who to the superficial obser\cr appear so siiperiorl}' 

 accommodated. The sheerwater is most frequently seen skimming close along shore, 

 about the first of the flood. I have observed eight or ten in company passing and 

 rej)assing at high water, dipping with extended neck their open bills into the water with 

 as much apparent ease as swallows glean up flies." So much for the speculations of M. 

 BufFon. 



That able naturalist, -Mr. Darwin, says: — ''I saw this bird both on the east and west 

 coast of South America, between latitudes 30^ and 4o*-\ It frequents either fresh or 

 salt water. Near Maldonado, in May, on the borders of a lake wliich had been nearly. 

 drained, and which in consequence swarmed with small fuy, I watched many of these 

 birds flying backwards and forwards for hours together close to its surface. They kept 

 their bills wide open, and witli the lower mandiblo half-buried in the water. Tlius 

 skimming the surface, generally in small ilocks, tiiey ploughed it in their course ; the 

 water was quite smooth, and it afforded a curious spectacle to behold a flock, each bird 

 leaving its narrow wake on the mirror-like surface. In theii- flight they often twisted 

 about witli extreme rapidity, and so dextei-ously managed, tliat tlu^y plougiied up small 

 lish with their projecting lower mandibles, and secured them with tlie upper half of their 

 scissor-like bills. This fact I repeatedly witncssDd, as like swallows fliey continued (o 

 fly backwards and forwai'ds close befoi'e me. Occasionally, when lea\ iug the surface of 

 the water, their flight was wild, irreguhir, and rapid ; they then also uttered loud liarsli cries. 

 When these birds were seen fishing, it was ()b\ious tluit tiie length of their primaiy 

 feathers was (piite necessary in order to keep their wings dry. S\'hen thus enipl(n(<l, 

 their forms resembled the symbbl by \\lucli many artists repi'cs /ut marine biids. Tiic 

 tail is much used in steering their irregular course. 



" These birds arc connnon far inland, along the course of the Rio Parana ; and it is said 



