In 1998, two known breeding
pairs nested on Sand Island. Constant monitoring aids in accurate
counts and identification of nesting sites which are difficult to
locate because of their scattered distribution.
Feeding Habits
Typically solitary feeders
though sometimes seen in pairs. With folded wings, white-tails hit
the water and completely submerge to seize and swallow prey before
flight. Prey consists of fish and squid.
Breeding
Courting birds fly in
parallel, with streamers from bird above turned downward toward
mate. Fly together in shallow glides. Begin nesting at four years
of age.
Nest year round with
peak activity from March through October. Primarily a cliff or cavity
nester. On Midway, birds nest in cavities of tree limbs, root bases
of ironwood trees (Casuarina equisetfolia) and/or other secluded
spots. A single egg is laid and incubated (40-42 days) by both adults.
Lacks brood patch. Average incubation shift lengths range from about
4-8 days. Chicks are tightly brooded for the few days after hatching.
Unlike other Pelicaniformes, adults regurgitate food by putting
their bills down the gaping chick's throat. Average chick fledge
times vary between 10-12 weeks.