220 BRITISH BIRDS. 



small end, about half an inch deep. I liave also found this 

 peculiarity in eggs of the Common Partridge. 



C. W. COLTHRUP, 



[The presence of a cap, or more usually a zone of blue-green, 

 has been noticed on the eggs of many Waders as well as on 

 those of some Terns and Gulls, It is probably due to the 

 pressure of the sphincter muscle preventing the deposit of 

 superficial colouring matter after the shell has absorbed 

 the first deposit of colouring matter (biliverdin) in its soft 

 condition. This green deposit is general, as may be seen 

 by holding the egg up to the light. — F.C.R.J.] 



AVOCETS IN SUSSEX. 

 On September 3rd, 1910, Mr. M. J. Nicoll, whilst walking on 

 the Parade at St. Leonards, saw a flock of seven Avocets 

 {Becurvirostra avocetta) flying in a westerly direction about 

 fifty yards from the shore. The birds settled at Pevensey 

 Marshes, some few miles west of St. Leonards, where one 

 w^as shot the same evening. Two were shot the next day 

 (September 4th) and one on September 5th. These four 

 birds were sent to Mr. Bristow for preservation, where I saw 

 them on September 16th. They were all four adult birds, in 

 fine condition, and on dissection proved to be two cocks and 

 two hens. H. W. Ford-Lindsay. 



BLACK-THROATED DIVER IN WESTMORLAND. 

 On February 24th, 1910, after two or three days' gale, a male 

 Black-throated Diver {Colymbus arcticus) was shot on Lake 

 Windermere by M. Brockbank. It is an adult bird in winter- 

 plumage and is now in my possession. D. G. Garnett. 



NOTES ON BIRDS IN ORKNEY IN 1910. 



Blackbird {Turdus merula). — An increasing species nesting 

 all over the mainland (Pomona) not only where there is 

 cultivation and in the liedges, but also on the moors on the 

 ground in heather-banks. Average number of eggs noted five. 



The Mistle-Thrush {T. viscivorus). — At least three pairs 

 on the mainland (Pomona), near Finsto\\Ti. We saw two 

 nests in mountain ash trees, each with four eggs on May 20th. 

 This bird has not nested, I believe, before in Orkney, and only 

 recently has been noticed as a regular visitor. 



Whitethroat {Sylvia cinerea). — A pair were in the garden 

 at Balfour Castle, Shapinsay, between Slay 30th and June 3rd, 

 and from their behaviour had a nest close by. 



Blackcap {S. atricapilla). — We saw two pairs between 

 May 30th and June 3rd, and one pair on the Island of 

 Shapinsay undoubtedly had a nest. 



