148 THE GULLS 



mass the size of a walnut, and keep it between the mandibles for the 

 young to peck at. 1 



The young are able to fly well in July, and towards the end of this 

 month both old and young quit the gullery. The species is to be seen 

 round our coasts in winter, also inland, where it is in parts almost as 

 familiar an object in the fields as the rooks, and like them, sometimes 

 with them, is to be seen following the plough. Its migratory move- 

 ments are somewhat confusing, and have yet to be clearly made out. 

 What is known of them is summarised in the " Classified Notes." 



It is worth noting that when flying to roost the species has been 

 seen to adopt the chevron or V-shaped formation. This was observed 

 by Mr. T. A. Coward in the case of the birds that roost at Rostherne 

 Mere, in Cheshire, where they are to be seen in very large numbers 

 every evening from November to February. 2 



Full particulars of the food of this omnivorous species will be found 

 in the " Classified Notes." It obtains it not only on land and water but 

 also in the air. Often in the twilight of a summer evening the white 

 forms of the birds may be seen flitting here and there in pursuit of 

 moths and other insects. 3 



Two peculiarities in its feeding habits call for special notice. One 

 has been called " pool dancing " by Professor Patten, and is thus de- 

 scribed : " It is this : a blackheaded-gull wades into a little pool, the 

 water of which is only deep enough to cover part of its feet ; it then 

 lowers it head and looks at the bottom. Finding no food, it at once 

 commences to prance up and down, stirring up the sediment, out of 

 which it picks various marine creatures and fragments of seaweed. I 

 have seen many of these birds at this performance along the mud-flats 

 of Dublin Bay." 4 Mr. A. H. Patterson has noticed the same several 

 times on the Breydon mud-flats (Norfolk), and compares it to the 

 dancing of a hornpipe. 5 



1 In litt. * Fauna of Cheshire, i. 428. Cf . also Naumann, Vo'gel Mitteleuropas, xi. 212. 



3 Ussher and Warren, Birds of Ireland, p. 330 ; Zoologist, 1843, 246 ; 1844, 455, 577-78 ; 1902, 216. 



4 Patten, Aquatic Birds, p. 414. 



5 Notes of an East Coast Naturalist, p. 142. 



