The Land of the Hills and the Glens 



a spring tide. On most of the smaller grassy islands Arctic 

 terns were nesting, and in passing, one could see them 

 brooding on their nests or arriving with their catch of 

 fish. 



Periodically they would, on a sudden impulse, take wing 

 together and fly swiftly out to sea, gliding low over the 

 water's surface, and returning to their nests within the space 

 of a minute or so. It would be interesting to learn the 

 reason for these sudden excursions. Certainly the common 

 gulls nesting near appreciated them, for they gave them the 

 opportunity of purloining a few of the eggs before the terns 

 could return and drive off the marauders. 



Depending, as they do, entirely on the presence of the 

 small fry on which they feed, the terns will either not nest 

 at all, even in a well-known haunt, or will leave it before 

 nesting is completed, should the fry be absent from the neigh- 

 bouring waters. An interesting case is that of some grassy 

 islands in the Sound of Mull. The terns were nesting here 

 in their thousands in a certain year. The following season 

 — a very cold summer, and with much northerly wind — 

 not a single bird was to be seen. The year after this they 

 had returned, though, I think, in reduced numbers, while 

 in the fourth season the islands had their former dense 

 population. 



In this latter year the arrival of the terns seems to have 

 been considerably later than usual. On May 14 and 15 

 great numbers of the birds were fishing in a bay a good 

 deal to the south of these nesting-grounds, and it was not 

 until May 23 that they w^re first seen at a well-known 

 nesting-haunt where they usually arrive punctually on 

 May 6. A small island on which they nest was found by 

 the terns to be already occupied by a colony of black-headed 

 gulls. A fierce battle commenced, continuing all that day 

 and into the night, and recommencing early next morning. 

 At length the terns withdrew, leaving the gulls in possession, 

 but a few days later the sea swallows returned with reinforce- 



96 



