138 THE SCOTTISH NATURALIST 



question, which indeed is not an easy one to settle. A 

 precise solution almost demands direct evidence of arrivals, 

 or, in its place, a series of continuous observations, with the 

 assurance, especially necessary in a case such as that of the 

 Waxwing, which is known to move from place to place in 

 search of food, that birds observed in successive days were 

 fresh arrivals and were not earlier arrivals which had moved 

 from their first landing place. 



In the present instance an accumulation of evidence 

 points conclusively to a long-continued immigration, the 

 period of which can be fairly accurately determined. The 

 birds seen up to 17th or i8th November occurred singly, in 

 pairs, or in very small flocks, quite insufficient to account for 

 the numbers observed in various places from the i8th 

 onwards. A fortunate series of observations made in 

 successive days at Joppa, a point affording a good landing 

 to migrants coming from a north-easterly direction, seems 

 to point to fresh arrivals. On 15th November Mr Gray 

 observed there in his garden four Waxwings, on the i6th 

 there were six, on the 17th thirteen, and on the i8th nine, 

 after which the flock, already dispersing, moved to fresh 

 quarters. A second series of observations carries on the 

 story : At Holy Island, where the birds stayed only a few 

 hours before moving on, so that each observation marks a 

 fresh arrival, Mr W. G. Watson noted one Waxwing on 14th 

 November, three on the 20th, one on the 26th, and one on 

 the 29th. After 29th November I have no records of obvious 

 new arrivals on the east coast except about ist December, 

 when over a score appeared at Cley in Norfolk, and several 

 appeared about the same day at Hunstanton in the same 

 county. At Golspie on the east coast of Sutherland several 

 were seen on 8th December, but these cannot safely be 

 regarded as fresh immigrants, since there were already 

 many Waxwings in the neighbourhood. 



It maybe concluded, therefore, that the immigration, begun 

 on 9th or loth November, continued until the early days of 

 December, a period of twenty-three to twenty-six days. 



TJie Numbers of Waxwings Involved. — The Waxwing 

 invasion of 192 1 seems to have been the largest that ever 



