PORANGAHAU—THE CASPIAN TERN 5 
because it is the better shielded from human 
trespass, because it stands guarded by treacherous 
mud flats and extensive areas of private property. 
Perilous as may be waves and winds, it is the 
opinion of the local sea-fowl that the presence of 
man is more dangerous still. It has come about 
therefore that Terns, Gulls, and Kittywake chiefly 
build immediately below the crest of the northern 
beach and on the edges of the lagoon. 
Thus although on the southern shore natural 
conditions favour the birds, yet the northern is 
chosen. Sea-birds breeding about this river estuary 
have been driven by settlement from the natur- 
ally safer to the naturally less secure locality ; it 
is but an example of one of the many factors that 
throughout modern New Zealand lessen, season by 
season, the numbers of shore birds. The Caspian 
Tern, Sea Swallow, and Kittywake of this beach 
thus have the restricted choice of building beneath 
the crest of the beach, thereby risking the over- 
whelming of their colonies by specially heavy 
Seas, or of planting their nests on the lagoon’s 
edge, thereby hazarding its rise by the inrush 
of the ocean. Some of the birds elect the one 
danger, some the other. One great Ternery 
extends beneath the crest of the beach, another 
along the edge of the lagoon. The opinions of the 
three pair of Caspian Tern also appeared to differ 
as to which spot was the less perilous, one pair 
