Red-footed Booby
The increase from six birds of this species seen in March to 71
seen in April is explained by two factors. First, a feeding flock of 40
was seen in the company of 200 Sooty Terns on the first day out of Oahu,
and, second, 28 birds were seen within sight of Oahu on the last morning.
This area was passed during the night on the March cruise.
Great Frigatebird
Only two birds of this species, both along the western edge of the
grid area, were seen in April, indicating a very small but possibly regular
occurrence in the western portions of the grid area in the spring.
Sooty Tern
Numbers of this species increased 30% from 1261 in March to 1633 in
April. The difference can be accounted for by the numbers seen during
the last morning of the April cruise to the north of Oahu, the same area
having been covered at night in March. Three density centers were found;
first, within 100 miles of Oahu, second, along the western side of the
grid, and third, in the southeast corner.
Noddy Tern
All 165 Noddy Terns seen during the April cruise were seen within
50 miles of Oahu where there is a large breeding colony.
Hawaiian Noddy Tern
All 420 of this species seen during the April cruise were seen
within ten miles of Hilo harbor. This species nests along the rocky cliffs
of the coast of the island of Hawaii.