BIRDS OF THE HUMBER DISTRICT. 205 



out the year j the mature birds only in the autumn, 

 winter, and early spring. In the summer, those birds 

 of this species which we see off the coast are in the 

 second and third year's plumage, and not yet 

 breeding. 



The mature birds leave the river to go northward 

 about the end of March or commencement of April ; 

 and we find them again on the river-flats early in 

 July, in company with the young of the year. I have 

 seen large numbers at Spurn and off the mouth of 

 the Humber in August, as many as seventy or eighty 

 together. These flocks are composed of the old birds 

 and their young, the Gulls in the second and third 

 year's plumage still keeping apart. 



The Lesser Black-backed Gull nests annually in 

 large numbers on the Earn Islands, and is a very 

 common species on the coast of Northumberland. 



264. LARUS ARGENTATUS, Gmelin. Herring-Gull. 



A common Gull in the river and along the coast. 

 Like the preceding, it leaves us in the spring for its 

 northern breeding- stations. 



Nests on the cliffs near Filey, also on the Farh 

 Islands, but not nearly so plentifully as the Lesser 

 Black-backed Gull. Nests also on the Berwickshire 

 coast, near St. Abb's Head, where it is extremely 

 common, taking the place of L. fuscus, which is by 

 far the most numerous species on the Northumber- 

 land coast. 



