1919-] Birds in the North of France. 75 



Hsematopiis ostralegus. Oyster-Catcher. 

 Flocks ill number between ten and twenty frequently 

 seen in the Canclie estuary in October and November. 



Arenaria interpres. Turnstone. 



The Canche estuary is not suitable for this species ; single 

 birds seen there on 12 May and 3 November. 



Larus canus. Common Gull. 



Odd birds in the Canche estuary on 17 October, and a 

 great increase on the following day; common there and at 

 Boulogne in October and November. 



Larus argentatus. Herring-Gull. 



Common in the Canche estuary in October and November. 



Larus marinus. Greater Black-backed Gull. 



A few in the Canche estuary on 17 October, and many on 

 the following clay ; in large numbers subsequently in October 

 and November, especially on the big sandbank at the river 

 mouth ; some in the estuary at the end of July 1918. 



Larus fuscus. Lesser Black-backed Gull. 

 Many in October and November in the Canche estuary 

 and at Boulogne ; some at any rate were L. fuscus affinis. 



Larus ridibundus. Black-headed Gull. 



Only occasionally seen inland: two at Peronne on 17 

 April ; one at Flixecourt, near Amiens, on 4 July; three at 

 Gorre on the La Bassee Canal on 7 January ; twenty over 

 Adinfer Wood, south of Arras, on 23 March, 1918. 



Common in the Canche estuary in October and November, 

 and July 1918. 



Hydrochelidon nigra. Black Tern. 



On 31 July, 1918, I saw one resting at the edge of tlie 

 channel in the Canche estuary at low tide ; after a time it 

 began to feed, flying slowly down stream against a liglit 

 breeze, dipping down to and sometimes touching the water, 

 and then flying quickly back up stream to its starting-place ; 



