SANDWICH TERN. 
77 
breeding-season the immense numbers of these Terns 
that resort together, cover the ground beyond imagination 
in some of their favourite localities, among which we must 
particularly enumerate the Islands of Norderoog, Sude- 
roog, Pelworm, and Arnroin, off the west coast of Schleswig, 
and the coast and sand-banks of Holland and Friesland, 
where the ground is so entirely covered with them, that 
their appearance can be compared to nothing else than 
snow; and when the birds happen to take wing simul¬ 
taneously, they form, without exaggeration, a perfect white 
cloud. 
W^e presume to make an observation on the subject of the 
Sandwich Tern, to account for its not having been noticed 
by British Ornithologists before the time of Dr. Boys, and 
we have the opinion of Dr. Latham also, to the same effect; 
namely, that this Tern has the peculiar habit of taking up 
its summer residence in a certain spot, and after a time to 
change it so entirely for another, that it is not again to be 
met with for many years : on the Island of Stiiber, for 
instance, the present species used formerly to be very 
numerous, but now, and for many years past, there is not a 
single individual to be found. That this Island of Stiiber 
has shared the same fate as the Goodwin Sands, by being 
reduced to a sand-bank, might, in a great measure, account 
for the abandonment of the island, but who can say whether 
this very circumstance may not have contributed to extend 
the Sandwich Tern to the shores of Great Britain, and thus 
exonerate the ornithologists of former days. 
The present species is exclusively a sea-bird, and does not 
even enter rivers out of sight of the ocean, nor is it found 
inland under any circumstances ; it is a migratory species, 
arriving in our latitude by the end of April, and remaining 
until the end of August or the beginning of September, 
