140 THE SCOTTISH NATURALIST 



It would not be safe to assume that each of these records 

 refers to birds that had not been previously observed, for the 

 Waxwings betrayed a strong tendency to wander from place 

 to place as the food supply gave out. For example, the last 

 record of about a dozen birds at Pease Dean clearly refers to 

 the residue of the large flocks seen about 21st November in 

 the same district. But this objection cannot apply to the 

 majority of the records which were gathered from widely 

 separated localities. 



The total number of Waxwings of the 192 1 immigration 

 of which I have received notice, and omitting of course dupli- 

 cate references to the same flock at the same time and place, 

 amounts to over 1000 individuals; but I would again repeat 

 that this number certainly includes some overlapping due to 

 the appearance of the same birds successively in different 

 places. On the other hand, it refers only to birds actually 

 seen or estimated from close observation, and therefore must 

 fall far short of the true number of the immigrants, many of 

 which must have landed and remained undiscovered in the 

 less populous parts of the country. 



In the following section I shall have occasion to state 

 some of the total numbers observed on different days. 



TJie Waves of Iviviigration. — I have shown that the influx 

 of Waxwings continued over a period of rather more than 

 three weeks, from at least the loth of November till at least 

 the 1st December; but during this period the succession of 

 arrivals was by no means constant or regular. It would 

 appear that the migrants reached this country in waves, and 

 here I set down the facts that point to successive influxes, 

 leaving for a later section a discussion of the meteorological 

 factors which seem to be associated with them. 



As it has been found to be impossible altogether to 

 eliminate overlapping of records, and as it does not seem 

 to be advisable to confine attention only to arrivals on the 

 coast, since migrants may easily have made a first landing 

 some distance inland, I have made use of the total numbers 

 of individuals recorded each day in Great Britain. In so 

 doing I recognize the dangers of error not only from these 

 sources, but also from the incompleteness of the records 

 themselves. While, therefore, the numbers quoted cannot 



