100 THE TERNS 



A full and careful study of the plumage of the young from the down 

 stage onward is given by Dr. L. Bureau in his " Monographie de la 

 Sterne de Dougall," published in the Proceedings of the Fourth International 

 Ornithological Congress (1905). The same writer also gives his observa- 

 tions on the breeding season and time of departure as observed by him 

 off the coast of Brittany. Here the birds breed earlier than in Great 

 Britain, and probably arrive earlier. The first eggs are to be found 

 from about May 16th to 20th, whereas in Great Britain the more usual 

 time for full clutches is from the first week in June onward, and many 

 fresh eggs may be found, when the birds have not been disturbed, even 

 in the second week of June. The first eggs were hatched in Brittany 

 about the end of the first week in June, while both old and young, in 

 cases where the colony has not been disturbed, leave the islands about 

 July 15th. In cases where the first eggs have come to an untimely 

 end, the stay may be prolonged even to the end of August, but by the 

 first days of September all have disappeared. In one colony observed 

 by M. Levesque they departed between July 25th and 28th. 



After the breeding colonies have been abandoned, Dr. Bureau 

 states that the birds do not forsake the neighbourhood altogether, but 

 reassemble in large flocks, composed of old and young birds, on the 

 outlying islets, and have been observed from the beginning of August 

 up to the end of October. The latest date of which he has any record 

 is that of two young birds obtained on October 22, 1896. 



One last word on the habits of this bird. Mr. E. G. Potter 

 (Zoologist, 1899, p. 83) suggests that the roseate-tern is accustomed 

 to rob the other terns with which it breeds, when it is feeding young. 

 The evidence quoted is chiefly second-hand, and in some cases 

 suggests a confusion of species, but, if correct, gives a possible clue to 

 the disappearance of small bodies of roseate-terns from large colonies 

 of other species. 



