500 Dr. A. L. Thomson : Besults of a Study of [Tbis, 



0£ the above, 22 reappeared during their firsi year, 

 2 during their second, 1 in its third, and 1 in its fourth. 



The first column of the seasonal analysis indicates that 

 the native birds decrease in numbers in winter in Scotland 

 and the north of England, and there is indeed no evidence 

 from this source that any remain throughout. The other 

 columns show that the birds may reach Ireland and south- 

 western France. 



There is also one isolated record (Case 229) of a bird 

 marked otherwise than as a nestling ; one of four birds 

 marked at nit^ht on the shore near Aberdeen on 3. 10. 10 was 

 recovered near the same place on 20. 7. 11. 



Witherby's records (2o) include a Black-headed GruU 

 marked in Yorkshire and recovered from the Azores in its 

 first winter, and another marked as a chick in Cumberland 

 in 1910 and reported from Aberdeenshire, over 200 miles 

 farther north, on 20. 2. 11. The species has also been studied 

 by Thienemann (16), birds marked as chicks at Rossitten, 

 at the south-eastern corner of the Baltic, being reported in 

 winter as far afield as the south of England, the Bay of 

 Biscay, the Balearic Isles, the south of Italy, and Tunis. 



VI.— THE MALLAllD {Anas bosohm Linn.) : 

 ANALYSIS OF EECORDS. 



The Mallard is found all th(? year round in the British 

 Isles, but it is known to be a winter visitor and a bird of 

 passage as well as a resident, and, as in so many other 

 cases, the first problem is accordingly the separation of 

 the movements performed by the native and innnigrant 

 birds respectively. Birds of this species are frequently 

 hand-reared, often from eggs imported from other districts, 

 and it is to cases of this kind that most of the records 

 refer. 



Many hand-reared ducklings were marked at Pitcaple 

 Castle, Aberdeenshire, in 1910, but owing to the loss of 

 some of the notes the total is uncertain. Of these, 13 were 

 recovered, ten of them in the same district (seven on the 



