258 CATALOGUE OF BIRDS. 



visiting our islands about the month of May for 

 breeding- purposes, departing again towards the end 

 of September. 



According to the best ornitholoo^ical authorities, the 

 Common Terns' distribution over the British Islands 

 may be said to be considerably to the south of that 

 occupied by the Arctic Tern ; the two being so very 

 similar in plumage as to require an expert to tell the 

 difference, and their habits and general character- 

 istics so much the same, treatment under one head 

 will be quite sufficient. Howard Saunders gives the 

 following boundary for the Common Tern : " west 

 coast of Great Britain as far north as the Island of 

 Skye, the Channel, and east coast of England as far 

 as the Moray Firth." I have met with scores of 

 Terns breeding on the islands in some of the fresh- 

 water lochs in the Hebrides which I have hitherto 

 taken to be the Common Tern, but on referring to 

 Howard Saunders's " Manual," he states that he has 

 had no conclusive evidence of their being there. 

 All I can say is that I must have mistaken the one 

 for the other, a mistake which might easily occur. 



On looking at the two species closely one finds 

 that the Arctic Tern has a blood red bill and is 

 rather darker on the breast, while the bill of the 

 other is orange-red tipped with very dark brown, 

 and the breast is lighter in colour. The chief 

 interest in the Tern is when it is enoragred in fishing' 

 operations, which are most graceful ; the bird at 

 such times soars up in the air to the height of from 

 fifty to sixty feet, then hovering for a few seconds 



