I9I-. Notes. 63 



NOTES, 



ZOOLOGY. 



The Twaite Shad in Killarney Lakes. 



Mr. John Hilliard has sent mc a Twaite Shad {Clnpea fmta) from Killar- 

 ney ; the fish is nine inches long and was captured on January 31st, when 

 it w^as found gasping on top of the water. Mr. Hilliard writes me that he 

 has found several Shad washed ashore and it seems probable that some of 

 the Twaite Shad that enter Killarney in May do not return to the sea during 

 the summer, but pass the winter in the lakes. Mr. Hilliard reminds me 

 that the Killarney Lakes are only five miles from the tidal waters of the 

 Laune, and is not satisfied that Shad winter in the lakes. But this seems a 

 more probable explanation than that they run up from the sea in the winter, 

 for it is known that Shad, like other anadromous fish, such as Salmon and 

 Smelt, may form non-migratory lacustrine colonies under favourable 

 conditions, and in the large lakes of northern Italy the permanently fresh- 

 water Shad have become specifically distinct from their migratory relatives. 

 I am not acquainted with any other case of Shad wintering in fresh water 

 in the British Isles. The specimen also has the interest that the man 

 who caught it mistook it for a Pollan, thus confirming a suspicion I have 

 entertained for some time, that the so-called Pollan of Killarney is the 

 Twaite Shad. In 1852 a Mr. Ffennell exhibited to the Dublin Natural 

 History Society, Pollan from Lough Neagh and from Killarney, and pointed 

 out differences in the shape of the head and the gill-covers ; the pre- 

 sumption that the so-called Pollan of Killarney were Twaite Shad is 

 strengthened by the facts that they were captured in May, and that the 

 Pollan of the Shannon and of Lough Erne do not differ from those of Lough 

 Neagh in the shape of the head and opercles. 



C. Tate Regan. 



British Museum (Natural History). 



Little Auks in Co. Dublin. 



Two specimens of the Little Auk {Mergulus aile), an irregular winter 

 visitor to Ireland, usually after stormy weather, were found alive in County 

 Dublin during the first w^eek of February of this year. The birds were 

 quite tame, but unfortunately refused to take any food and only lived 

 for a short time. One was found at Portmarnock by Miss Browne-Clayton 

 and the other at Rathfarnham by Miss Wize. 



A large visitation of the Little Auk to the British Islands would seem 

 to have occurred at the beginning of February. Mr. W. Wilhams informs 

 me that he has specimens from different parts of Ireland, and several notes 

 have appeared in The Field and other English newspapers of captures of 

 this bird in England. 



Mr. Ussher in " The Birds of Ireland." says that this bird has usually 

 been obtained in Ireland during the months of November, December, and 

 January, and refers to the absence of records for February. 



A. R. Nichols, 

 National Library, Dublin. 



