126 



The Stork-like Birds 



there is a very remarkable excrescence near the middle of the upper mandible, 

 which is assumed only during the breeding season. This excrescence or "center- 

 board," as it is called, is described as follows by Mr. Ridgway: "It is assumed 

 gradually in the spring, reaches its perfect development in the pairing season, 

 and it is dropped before or soon after the young are hatched. Frequently it 

 consists of a single piece, nearly as high as long, its vertical outlines almost 

 parallel, and the upper outline quite regularly convex, the largest specimen seen 

 being about three inches high by as many long. More frequently, however, it is 

 very irregular in shape and usually less elevated." Its function is purely prob- 

 lematical. Coincident with the shedding of this appendage in this species the 

 "nuchal crest falls off, and in its place a patch of short, brownish gray feathers 

 appears; this disappears with the fall moult, when the occiput is entirely un- 

 adorned, there being neither crest nor colored patch." 



The Pelicans (Pelecanus), of which ten species are now recognized, are widely 

 distributed throughout the tropical and temperate regions of the Old and New 

 Worlds, North America laying claim to three species. They are a very old 

 group, for some nine fossil forms have been described, the oldest being from the 

 lower Miocene of France. Their food consists almost entirely of fish, of which 

 they capture great numbers. 



FIG. 38. American White Pelican, Pelecanus erythrorhynchos. 



Brown Pelican. The following account of the manner of feeding of the 

 Brown Pelican (P. occidentalis] is from the pen of Dr. Brewer: "Birds of this 

 species are said to feed chiefly during the rising tide, wandering in extended trains 



