156 THE GULLS 



British Isles, one form or another of it being found in most parts of 

 the northern hemisphere ? No answer to the first suggests itself at 

 present. The probable answer to the second is that the success of 

 the herring-gull is due to the fact that, for some reason, it has proved 

 the most adaptable in its nesting-habits. It not only nests where its 

 congeners nest, on tops of islands and cliffs, on moor or shore, but 

 also on the face of precipitous cliffs, which they avoid with the 

 exception of an occasional lesser blackbacked-gull. 



All four are gregarious in the breeding season, but single pairs 

 may be found by themselves, or associated with another species. 

 Solitary single pairs of breeding common-gulls are not infrequently 

 seen on the Scottish hills. 1 Single pairs of greater blackbacks are 

 likewise not uncommon. A notable instance is provided by a pair 

 which elected to nest on a grassy island in Lough Conn (N. Mayo) 

 amid a large colony of blackheaded-gulls. To the latter the honour 

 proved to be anything but agreeable, for no small number of their 

 eggs went to satisfy the appetite of their two gigantic relatives. 2 



On the interesting subject of displays or gestures very little in- 

 formation is available. Herring-gulls in captivity have been seen 

 bowing to each other, accompanying the performance with a note, not 

 described. The male selected his mate from three females, and it is 

 stated that the chosen one persecuted her two companions, prompted, 

 perhaps, by some primitive sense of jealousy. 3 Mr. E. Selous, in a 

 chapter on the blackbacked and herring-gulls, observes that " Gulls 

 have no very salient or pronounced courting antics I mean I have 

 observed none, and, in the same sense, there is no special display of 

 the plumage by one sex to the other. When amorous, they walk 

 about closely together, stopping at intervals and standing face to face. 

 Then lowering their heads, they bring their bills into contact, either 

 just touching or drawing them once or twice across each other, or else 

 grasping with and interlocking them like pigeons, raising them a little, 



1 Harvie-Brown, Fauna of the Moray Basin, p. 215; ibid., Fauna of Argyle and the Inner 

 Hebrides, p. 190. 



5 Zoologist, 1911, 349. Irish Naturalist, 1898, 255 (Win. M'Eiidoo). 



