148 THE BIRDS OF BERKS AND BUCKS. 



observed flying over the reservoirs at Drayton Beau- 

 champ at the time of its migration. Several others 

 have come under my notice which have been procured 

 in this neighbourhood in autumn, but the exact dates 

 of their occurrence could not be ascertained. An 

 immature Common Tern, in the collection of Mr. 

 Sharpe, was shot a few years since at Cookham. 

 Another, in the possession of Mr. Mills of Bisham, 

 was killed near that place by himself Mr. Gould 

 told me that while on the river near Maidenhead, 

 towards the end of May, 1866, he shot a common 

 Tern together with an Arctic and Black Tern, all of 

 which are now preserved in the collection of Mr. 

 Grefell, at Taplow Court. Mr. Dalziel Mackenzie 

 wrote me word that this bird has been observed 

 flying over the Thames near Pangbourne. 



Arctic Tern {Sterna arctica). This species had 

 long been confounded with the Common Tern, which 

 it closely resembles, but the distinctive characters of 

 both have been pointed out by Mr. Temminck (Man. 

 d'Ornith.), and more recently and clearly by Mr. 

 Harting, in his * Birds of Middlesex.' It is occasion- 

 ally obtained in the counties of Buckinghamshire and 

 Berkshire during the periodical migrations in spring 

 and autumn, but it is never at any time numerous. 

 The Arctic Tern is occasionally seen at the Mars- 

 worth and Wilstone reservoirs, and at other large 

 sheets of water in the two counties. Many years 

 ago Mr. H. Daly shot one of these birds in autumn,. 



