1 92 1.] J3ird-Mir/)'ation In/ the Marhinq Method. 



409 



v.— THE BLACK-HEADED GULL {Lants ridihundus Linn.): 

 ANALYSIS OF RECORDS. 



The Black-headed Gull is found all the year round in the 

 British Tsle.5, and, as in the case of other sea-hirds, its 

 migratory movements are diflficult to distinguish. During 

 the course of the inquiry, 1,150 were marked, 31G of them 

 as chicks in the northeast of Scotland and 294 as chicks 

 in the north of England. The reappearances number 27 

 in all, or 2*3 per cent. 



Of those marked as chicks in the northeast of Scotland, 

 12 were recovered as follows : — 8 from the same or a neigh- 

 bouring district, 2 from more southerly parts of Scotland, 

 1 (Case 390) from Co. Down, Ireland, and 1 (Case 116) 

 from near Bayonne, Basses-Pyrenees, France. 



Of birds nuirked as chicks in central Scotland, 4 were 

 recovered as follows : — 3 from the same district or slightly 

 to the south, and 1 from the extreme southwest of 

 Scotland. 



Of those marked as chicks in the noi'th of England, 

 10 were recovered, all from the area of marking. 



TABLE XV. 



Seasonal Analysis of Reappearances of Black-headed Gulls 

 marked as chicks in scotland and the north of england. 



(* No records for March, April, or May.) 



