196 PATAGONIAN EXPEDITIONS I ZOOLOGY. 



Geographical Range. Coast, rivers and larger inland bodies of water 

 of South America. Lake Titicaca. Straits of Magellan. Coasts of Pat- 

 agonia and Chili. The coast of Peru. Probably resident and breeding 

 almost throughout its range. 



FIG. 119. 



Rhynchops melanura. Left foot. From a specimen in American Museum. Natural size. 



Though this species was not collected by the Princeton Expeditions, I 

 find mention made of a flock of "skimmers" in the notes of one of the 

 naturalists of the expedition, which refers undoubtedly to this bird. 



Darwin's account is of special interest. I quote (Voyage of the 

 "Beagle," Zoology, Birds, Gould, p. 143, 1841): "I saw this bird both 

 on the East and West coast of South America, between latitudes 30 

 and 45. It frequents either fresh or salt water. 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 skimming 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 se- 

 cured 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 utterd 

 loud, harsh cries. When these birds were seen fishing, it was obvious 



