92 



LONG-WINGED SWIMMERS. 



assume the adult dress slowly. Very social, 

 associating in large flocks, especially at night, 

 in winter when many hundreds gather to 

 sleep on the water. 



59. GREAT BLACK-BACKED GULL. 

 Our largest common Gull, 30; mantle, 

 dark slate, but it appears perfectly black in 



Fig. 64. 



Great Black-backed Gull. 



the distance; w^hite elsewhere and there is a 

 white wing band; bill yellow and feet pink- 

 ish, fig. 64. Young for the first year, rather 



