ARCTIC TERN 395 
is one of the few countries where it breeds on the islands 
of fresh-water lakes, such as Corrib, Mask, Carra, and 
Melvin, all situate in the western province. 
Early in May, the Arctic Tern arrives in our Isles, 
departing southward in August and September. Before 
migrating, adults and young may be observed flying together 
along the coast in search of food. 
Immature birds, one year old, are not often seen; they 
may be distinguished from Common Terns at a corre- 
sponding age by their entirely black beaks.? 
This bird is perhaps one of the bravest and most pug- 
nacious of its kind. I have seen a small flock not only 
assail, but even follow a Merlin over the sand, and with 
wild screams and dashing flight, completely hinder the 
little Falcon from following up the smaller shore-birds upon 
which it so largely preys. ‘‘ A flock has been seen to mob 
and drown a Hooded Crow” (Saunders). 
Flight.—The flight is particularly buoyant and on the 
wing the Arctic Tern is difficult to identify? from the Com- 
mon ; the latter is somewhat larger, and the fork of its tail 
is shorter. 
Voice.—The note, so often heard when the bird is over- 
head, sometimes sounds harsher, and more prolonged than 
that of the preceding species ; at other times the two voices 
are practically indistinguishable. 
Food.—This consists largely of fish captured after the 
manner of other Terns. 
Nest.—Marine islands fringed with loose stones and 
shingle, as well as sandy beaches, are the favourite nest- 
ing-sites, and immense colonies are frequently to be found in 
such places. The eggs, two to three in number, are laid 
either on bare rocks often quite close to the sea, or among 
fragments of dry grasses or seaweeds, or they may occupy 
a slight hollow in sand and shingle. They are subject to 
much variation in colour; some are light greenish-brown, 
1 On October 15th, 1890, I picked up an immature Arctic Tern on 
Bray beach, twelve miles south of Dublin. The bird, in its second 
autumn plumage, was fresh and in good condition, but soaking wet; it 
was probably washed ashore after a gale, 
? It is much easier to identify the two species when congregated on 
bare, rocky islands. I have quietly sculled a boat close enough to see 
the short feet and coral-red beaks of the Arctic Terns, an observation 
all the more evident when the birds are standing on a rock which is 
elevated to about the level of the observer’s eye. 
