OYSTERCATCHER AND NATURAL ENVIRONMENT. 429 



intimate nature of the probable inter-relations of the settle- 

 ments of a district has been observed in the Aberlady district. 

 The Aberlady, Eyebroughty and Lamb stocks have never been 

 known to visit each other's feeding-grounds for food. The 

 Aberlady and Eyebroughty stocks share Eyebroughty, as a 

 refuge. On one occasion a shooting party was landed on 

 Eyebroughty towards the time of high water, the boat which 

 brought them being sailed about in the vicinity. The Eye- 

 broughty settlement anticipated the boat's arrival by proceeding 

 towards the Lamb, on which they were observed through field- 

 glasses to alight, and where they evidently remained. The 

 Aberlady Bay waders arrived shortly after at Eyebroughty, and 

 were unable to land. They did not proceed to the Lamb, but 

 flew round and round high over Eyebroughty for nearly two 

 hours, until the ebb of the tide allowed them to return and 

 alight safely in Aberlady Bay. After Christmas, when the first 

 signs of nuptial activities begin to appear, visits are exchanged 

 between the Aberlady and Eyebroughty settlements, and between 

 the latter and the Lamb settlement ; but, so far as known, 

 never between Aberlady and the Lamb. 



As a possible indication of the need of controlling the food- 

 supply for the welfare of the settlement, by maintaining territorial 

 rights, there may be cited the results of a periodical examina- 

 tion of the sizes of shells opened by the Oystercatchers at the 

 Eyebroughty station in the course of winters 1908-1909, 1911, 

 and 1912. The results suggest that, in this area at least, the 

 food-supply is subjected to a considerable strain in meeting the 

 needs of the settlement. 



In the Eyebroughty area the average and largest sizes of 

 the mussels showed a continuous fall in the course of the winter 

 1908-9. 



Table S, Showing Seasonal Diminution in Size of Opened Shells of 

 Mytilus from "Mussel-Rocks," Eyebroughty: Winter 1908-9. 



Date. Number. Average. Largest Shell. 



Oct. 29th, 1908 10 3'lxl'4cm. 3-7 cm. long 



Nov. 16th, 1908 23 2-25xl-0cm. 2*8 cm. long 



Jan. 4th, 1909 .... ... 2'5 cm. long 



Jan. 26th, 1909 .... ... 1'9 cm. long 



