Sea Swallows 
These four species begin to arrive from the south 
in the latter part of May, apparently already 
mated, but with flirtations and jealousies enough 
to make things lively. Soon afterward, by the 
middle of June, they have scattered to their va- 
rious breeding grounds. While the Wilson and 
roseate species ordinarily build a rude nest, the 
arctic tern simply deposits its eggs on the bare 
sand. After the incubation season is over, those 
that are scattered on the various islands gather 
in larger groups, and in September are found 
in great numbers on the coast and inlets all 
about Nantucket. Their particular location at 
this season depends in part upon the movements 
of the blue-fish, inasmuch as they feed largely 
upon the smaller fishes by which blue-fish are 
attracted ; and fishermen are even said to rely 
to some extent upon the presence of terns to in- 
dicate where a school of blue-fish may be looked 
for. Lingering about their summer homes un- 
til fall, or, in pleasant weather, passing farther 
out to sea, they begin to leave for the south 
by the middle of October, and have all disap- 
peared by the last of the month, when their 
northern representatives, the gulls, with other 
hardy aquatic fowl, begin to arrive for the 
winter. 
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