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REPORT ON THE RESULTS OF RINGING 

 BLACK-HEADED GULLS. 



BY 



H. W. ROBINSON, m.b.o.tj., f.z.s.s. 



During the five years 1909-1913, 11,769 Black-headed 

 Gulls {Larus ridibundus) were marked as nestlings 

 under the auspices of the British Birds Ringing Scheme, 

 and of these 414, or 3.51 per cent., have come to 

 hand. By far the largest number — 8,096 (68.79 per 

 cent.) — \yeve marked at Ravenglass on the Cumberland 

 coast, so it is not surprising that 345 (83.3 per cent.) 

 out of the total of 414 returns, were Ravenglass-bred 

 birds. The movement of these young birds from 

 their birthplace is best described as a scattering — a 

 scattering Anth a decided southward tendency along 

 both the west and east coastlines, independent of the 

 situation of the gulleries whether on the west or east 

 side. Recoveries were reported of nestlings marked 

 at fifteen different gulleries, of which three were in 

 Scotland, one in Ireland, one in Wales, and the rest in 

 England. 



1. Ravenglass, Cumberland. 



8,096 ringed. 345 Recovered. (4.26 per cent.) 



As by far the largest numbers have been marked at 

 this guUery, and a reliable percentage of these has been 

 recovered, the results from this centre of ringing must 

 form the basis of this report. It may be said at once 

 that the recoveries do not reveal any one definite line 

 of movement. In the case of a bird such as the Black- 

 headed Gull, which probably has to move over a con- 

 siderable area to obtain its food in autumn and winter, 

 it seems fair to assume that movements within a fairly 

 large area are of little real importance. With this in 

 view I have arbitrarilv taken the area between the 



