HIGH MORTALITY AMONG YOUNG COMMON TERNS 275 



caught a fish, carries it towards the nesting place. 

 The sitting bird detects the approach of its mate from 

 a considerable distance, and answers the call. The 

 young now run out from below the sitting parent and 

 pick off bits of the fish, which is still held firmly in 

 the bill of the other parent. Thus the young obtain 

 their food free from gritty sand. Once, on my handling 

 one of the little birds only a day or two old, a 

 surprisingly large bit of sand-eel was regurgitated. 



(6) The supply of this food seems to vary greatly, as large 



numbers of fish are carried on some days, very few on 

 others. Cold and windy weather with rough seas 

 seem to diminish the supply seriously. 



(7) That the quantity of this food was very limited in 19 12 



was asserted by an experienced Ythan angler, who 

 states that it forms the food also of the sea-trout, 

 which are caught in good seasons in large numbers, 

 and that the summer of 191 2 was the worst for fishing 

 that he had ever known. He stated that an excellent 

 plan for obtaining a good basket of sea-trout was to 

 fish where Terns are seen securing fry. 



(8) No unusual mortality was noted among the Black-headed 



Gulls on the same nesting ground, only one young 

 gull being found dead. 



(9) No lower mortality was observable on the part of the 



colony nearer the sea where others recorded it 

 in 1 9 10. A. R. G. 



The Season 19 14. 



A short unfavourable period was noted in 1914, as already 

 mentioned, but otherwise this was an excellent season. No 

 dead young were to be seen until the last week of July, which 

 was characterised by cold, north-easterly winds, with rain and 

 rough seas. During this week the constant flights of old 

 birds carrying sand-eels practically ceased. On 9th August 

 forty dead chicks were counted in half an hour, while the 

 sandy slope near the chief nesting site was covered with 

 young birds apparently recovering from partial starvation, 



