84 



NATURAL HISTORY OF BIRDS. 



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

 dipped into, and ploughing, the surface, and the facility with which he procures his 

 food, cannot but consider it a mere playful amusement, when compared with the dash- 

 ing immersions of the tern, the gull, or the fish-hawk, who, to the superficial observer, 

 appear so superiorly accommodated." 



Darwin observed the skimmer in South America. That excellent observer gives 

 us the following account of its habits: "Near Maldonado (in May), on the borders 

 of a lake which had been nearly drained, and which in consequence swarmed with 

 small fry, I watched many of these birds flying backwards and forwards for hours 

 together, close to its surface. They kept their bills wide open, and with the lower 



mandible half buried in the water. Thus skim- 

 ming the surface, generally in small flocks, they 

 ploughed it in their course ; the water was quite 

 smooth, and it formed a most curious spectacle to 

 behold a flock, each bird leaving its narrow wake 

 on the mirror-like surface. In their flight they 

 often twisted about with extreme rapidity, and 

 so dexterously managed, that they ploughed up 

 small fish with their projecting lower mandibles, 

 and secured them with the upper half of their 

 scissor-like bills. This fact I repeatedly witnessed, 

 as, like swallows, they continued to fly backwards 

 and forwards, close before me. Occasionally, 

 when leaving the surface of the water, their flight 

 was wild, irregular, and rapid ; they then also 

 uttered loud, harsh cries. When these birds were 

 seen fishing, it was obvious that the length of 

 the primary feathers was quite necessary in order 

 to keep their wings dry. When thus employed, 

 their forms resembled the symbol by which many 

 artists represent marine birds. The tail is much 

 used in steering their irregular course." 



It has already been hinted at, on a previous 

 page, that the super-family PROCELLAROI- 

 DE^E might perhaps better constitute a sepa- 

 rate order, Tubinares. Their differences from 

 all the foregoing birds are many and important, 



and their affinities seem to be more with the Steganopodes and Herodiones than with 

 the gulls or the auks, to some of which many of the petrels show a remarkable external 

 and superficial resemblance. We will give their essential characters, as contrasted with 

 those of the Laroideae, in order to show this. The petrels are holorhinal, the gulls 

 schizorhinal ; the former have tubular nostrils, the latter normal ones ; whenever a 

 hind toe is present, it consists in the petrels, of one phalanx only, while, in the gulls, 

 the normal number of two phalanges is always present, however rudimentary the toe ; 

 in the petrels, the great pectoral muscle is disposed in two quite separate layers, an 

 arrangement unknown in the gulls, and the pectoralis tertius of the former is entirely 

 unrepresented in the latter ; the muscular formula of the legs in petrels is, as a rule, 

 A B X Y, a combination, so far as we know, never found in the gulls ; the form 



FIG. 36. Skeleton of giant fulmar. 



