210 Ornithology of the Delta of the Rhone. 



Hydrochelidon leucoptera (Schinz) 

 A White-winged Bla( 

 Fos on the 30th of May 



A White-winged Black Tern was seen on the Golfe de 



Hydrochelidon nigra (Linn.). 



Black Terns were observed in small numbers on several 

 etangs in the southern Camargue, and at the mouth of the 

 Petit Rhone^ down to the 19th of May, after which none were 

 seen. This species^ and others of its genus^ we expected to 

 find breeding in the Delta, but we failed to discover their 

 haunts, and miich doubt whether any of the group nested 

 there in 1894. 



Larus cachinnans, Pallas. 



This Herring-Gull was quite common on the shores of the 

 etangs of the southern Camargue, on the Rhone, and on the 

 Mediterranean. All the examples observed were, however, 

 in more or less immature plumage. 



Larus ridibundus, Linn. 



The Black-headed Gull was seen only on an island in the 

 Grand Rhone, just above its embouchure, on the 30th of 

 May. 



Larus marinus, Linn. 



An excellent view was obtained of an adult Great Black- 

 backed Gull on the Etang de Galabert, on the 27th of May. 

 A westerly gale was blowing at the time, which drove the 

 waters of the Mediterranean into the etang, and the bird 

 was observed slowly flying against the wind. Adult birds 

 are somewhat rare on the Mediterranean even in winter, at 

 which season usually this Gull is observed there. 



Stercorarius crepidatus (Gmel.). 



Two Richardson's Skuas were seen in pursuit of the 

 Terns — Sterna anglica, S. fluviatilis, S. niinuta, and Hydro- 

 chelidon nigra — at the mouth of the Petit Rhone on the 19th of 

 May. One of these was of the melanic form. Both were 

 adults, with long central tail-feathers. 



