BIRDS OBSERVED AT BALBRIGGAN. 177 



Common Tern (Sterna fluviatilis). — Constantly seen off shore, 

 but does not breed on mainland. 



Lesser Tern (S. minuta). — I saw numbers of these birds in 

 1903, but, strange to say, none in 1904. 



Black-headed Gull (Larus ridibundus). — Fairly common. 

 Our harbour-master persists in saying that there are two species. 



Common Gull (L. canus). — Plentiful in winter. 



Herring-Gull (L. argentatus). — Common at all seasons. 



Lesser Blaok-backed Gull {L.fuscus). — Not very common. 



Great Black-backed Gull [L. marinus). — A few pairs only. 



Kittiwake (Rissa tridactyla) . — Fairly common all the year 

 round. Called by the coastguards " the Pigeon Gull." 



Razorbill (Alca torda). — Fairly common. 



Guillemot (Uria troile). — A few only. 



Great Northern Diver (Columbus glacialis). — Fairly common 

 in winter. On Nov. 16th, at Cromwell's Harbour, about a mile 

 from this town, I witnessed a most interesting sight — five Great 

 Northern Divers swimming backwards and forwards in the har- 

 bour. I watched them carefully for nearly an hour, concealing 

 myself behind a rock ; they were not more than fifty yards away. 

 One was leader, and the others followed two by two. Every now 

 and then the leader screamed, diving immediately afterwards, 

 and the four others diving also at the signal. They were all in 

 winter plumage. 



Bed-throated Diver (C. septentrionalis). — Fairly common in 

 winter. 



Little Grebe (Podicipes fluviatilis). — Common at the "Bog 

 of the Pting," about three miles inland. 



Cormorant (Phalacrocorax carbo). — Very numerous. I have 

 not observed the Shag. 



Gannet (Sula bassana). — Frequently cruising off the harbour 

 in summer. 



Common Heron (Ardea cinerea). — Breeds in Hampton de- 

 mesne. I once counted sixteen Herons standing close together 

 at the Estuary, Malahide. 



White-fronted Goose (Anser albifrons). — I have twice noticed 

 small flocks passing south. 



Wild Duck (Anas boscas). — Plentiful at the bog and on the 

 sea. 



Zool. 4th ser. vol. IX., May, 1905. p 



