ON THE MOULTING OF THE HERRING GULL 



IOI 



Seasonal Occurrence of Moulting. 



During the summer and autumn, a sandy beach, such as 

 that which stretches for thirteen miles northwards from 

 Aberdeen, is thickly strewn with moulted feathers of Gulls, 

 which are daily swept away by wind and tide, or buried by 

 the blown sand. These, then, should afford an indication of 

 which Gulls are moulting at any particular time, and in the 

 table given below are embodied the results of a number 

 of representative collections made throughout the autumn 

 moult of 1908. These collections were made along the ten 

 miles of shore between the rivers Don and Ythan, but the 

 majority did not cover the whole of this distance. They 

 were mainly confined to the larger feathers, which could with 

 more or less certainty be identified ; it is not pretended 

 that they give more than a rough general indication of the 

 progress of the moult. 



Table summarising Representative Collections of Moulted Gulls' Feathers 



during Season 1908 (Aberdeen Coast). 



1908. 



Larns argentatus 

 L, mar inns 

 L. ridibundus 

 L. canns . 

 Rissa tridactyla 



I Adult 

 (Immature 



/Adult . 

 (Immature 



/Adult . 

 (Immature 



/Adult . 

 (Immature 



/"Adult . 

 (Immature 



The crosses are meant to give a rough indication of the relative preponderance of feathers 

 of immature and adult birds, in each species : 



x : few. x x : moderate. x x x : many. x x x x : very numerous. 



Before proceeding to review this table, we must add the 

 data from a number of individual birds examined, when 

 found dead on the shore from time to time. 



