15 
III. 
THE SEA SWALLOW, OR WHITE- 
FRONTED TERN. 
Tue Terns of the northern Porangahau beach 
during the season of 1910 were congregated in 
two great separate establishments—about two or 
three thousand in the larger, in the lesser rather 
fewer than quarter of that number. There was 
a third narrow line of a few score incubating 
birds on the southern beach. <A bird colony has 
a twofold interest: each member has its own 
idiosyncrasy, and may be studied as an individual 
citizen ; there is also the opportunity of watching 
its habits and customs as one of a gregarious 
multitude. 
The contours of these Porangahau ‘Terneries 
were approximately deltoid or lanceolate or oblong, 
dependent, I suppose, on shelter provided either 
directly, or indirectly and invisibly, by eddies 
consequent on conflicting currents of air. Unlike 
the Caspian Tern, the Sea Swallow is particular 
