54 Director's Annual Report. 
ful about the first of May. From that date on all through the 
summer months, they would hear them each night call out ‘‘A-o’’, 
as they left their burrows to fly out to sea. ‘They were commonly 
found colonized in the steepest parts of the pali, 500 or 1000 feet 
or more from the floor of the valley. The Uau asa rule, have 
their colonies higher up, seldom less than 1500 feet above the sea. 
Occasionally, however, both birds are found in the same colony—on 
rare occasions in the same hole. The Wailau natives who accom- 
panied me on the Uau hunt just described, verified these state- 
ments. ‘They were at some loss to account for the absence of Ao 
from among our catch of Uau, since last year, in June, they got 
both species. I heard the call of the Ao in the two valleys men- 
tioned several times, but am convinced that it is much the rarer 
of the two birds. 
Phaethon lepturus Lacep. & Daun. 
From the cliffs at the heads of the principal valleys, in fine 
weather, we can always see one, sometimes five or six, of the White- 
tailed Tropic Bird or Koae, gracefully floating about the cliffs far 
below. While no specimens were secured, I had no difficulty in 
satisfying myself that only the white-tailed species frequent the 
precipices there. As yet the bird is fairly common, being noted 
on a number of occasions, at different places about the island. 
However, it has already begun to suffer from the depredations of 
the mongoose, which is known to be on the increase everywhere 
on the island, especially in such localities as the Koae favors for 
breeding places. 
Fregata aquila Linn. 
The Iwa was seen on two occasions a considerable distance 
out at sea. Specimens are shot from time to time when they fly in 
close to the beach. 
Anas wyvilliana Sclater. 
No specimens of the Hawaiian duck were seen, and I doubt 
very much if there any now living in the island. Several persons 
informed me that some years ago it was always to be seen in the 
streams—frequenting the pools high up in the mountains. Lately 
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