Mr. W. C. Tait on the Birds of Portugal. 395 



wliicli time it has lost its summer plumage, large numbers 

 remaining through the winter. Early in March some 

 already begin to change to summer plumage, and by the 

 beginning of April nearly all have the black head and rosy 

 tinge of their summer plumage, and gathering in large flocks 

 exercise themselves in evolutions over the river Douro and 

 take their departure. It is possible that some breed in 

 this country. I saw one at Caminha on May 6th, 1880 ; 

 some on the river Guadiana, near Villa Real de Santo An- 

 tonio, in June 1884; also some in Vigo Bay, June 3rd, 1882, 

 but these may possibly have been L. melanocephalus. I 

 have read that in the Zoological Society's Gardens, London, 

 it was noticed that a captive L. ridibundus changed from 

 white to black plumage on the head by the gradual growth 

 of the white feathers into black, the white tips falling off; 

 but my observations do not agree with this. Having obtained 

 specimens in all stages of changing from the white to the 

 black head, I find that the black feathers are new ones, and 

 may be seen springing up already black in their sheaths 

 among the white feathers. It would be interesting to mark 

 some of these birds before departure in such a manner as to 

 render it conspicuous in its summer home, as, for instance, 

 by dyeing one of the wings or painting a coloured stripe across 

 it and stamping the address on the wing or tail-feather, so 

 that any one catching it might communicate the capture. 

 This would enable us to trace the route of migration. 



255. Larus melanocephalus (Natt.). 



In February 1882, Dr. Carvalho wrote me that among other 

 specimens which had arrived for the Coimbra Museum was 

 a young Adriatic Gull. 



256. Larus minutus. Pall. 



I saw a Little Gull with a black cap on the river Douro 

 among some Brown-headed Gulls, and on account of its 

 diminutive size I could not well have mistaken any other 

 species for it. 



257. Larus argentatus, Gmel. '^^ Gaiv6ta,'' Vianna, 

 Oporto, &c. ; " Falcoeira," Aveiro. 



The Herring Gull is resident in Portugal, breeding on the 



