1920.] Cape San Antonio, Buenos Ayres. 73 



It will be seen from tlie preceding how closely Mr. Swenk^s 

 notes and my own data in the far south approximate, and 

 the fatal deduction they lead to. 



410. Rhynchops melanura Sw. Black-tailed Skimmer. 



Iris dark brown ; bill either red or orange at base, re- 

 mainder black ; feet bright red or a light brick-red. 



Tlie Black-tailed Skimmer may perhaps not breed in our 

 locality, as judged by Claude Grant, who considers it only 

 a winter visitor. And I myself have no knowledge of its 

 doing so. But the mud-flats and sand-banks of our Rincones 

 are numerous ; whilst that district is a No Man's Land, and 

 of great extent. And I am moved to further entertain the 

 possibility by the fact that I have observed the species in 

 nearly every month of the year, particularly at such a time 

 as the middle of September in two different seasons (a pair 

 and a small flock of eight respectively), when on a similar 

 date Claude Grant found variou.s colonies nesting on the 

 River Paraguay. Again, Hudson gives its chief breeding- 

 ground as being the mud -banks and islets at Bahia Blanca, 

 far south of here, and on the Atlantic seaboard. Am I to 

 suppose, then, that these September birds of mine had not 

 yet made their way to the above-mentioned far-away localities, 

 or that they had found a suitable site with us ? The same 

 query attaches itself to a flock of over two hundred, seen 

 resting on a mud-flat on the Ajo river (above the little 

 town) when I travelled that route by launch on the 3rd of 

 November, 1915. 



Darwin's account of the Skimmer or Scissor-bill (as 

 quoted in 'Argentine Ornithology') shows the impress-ion 

 this extraordinary bird made on him at flrst acquaintance. 

 Similarly, I recollect my own astonishment when on the 

 30th of August, 1875 (not having then read ' The Voyage 

 of tlie Beagle'), I met a solitary specimen towards the 

 evening, at what we designated the"Estancia cafiada pass." 

 It was quartering a large stretch of open water, and was being 

 persecuted at the time by various Lapwings, which its swift- 

 ness of flight and agility in turning set utterly at naught. 



