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WEDGE-TAILED SHEARWATER
Do you wonder how some of our birds got their names? The shearwater,
for example. Many birds are names for the way they act or the
habits they have. The shearwater got its name because it is a
seabird that hunts for food by skimming close to the surface of
the water, then plunging through the waves to catch the fish or
squid it spotted from the air. "Shear" means to cut or slice through.
This bird seems to slice through the ocean spray as it flies in
search of food. So, it is a shear water bird. You may pick out
this bird by the way it flies close to the water as it searches
for its food. It is also possible to spot this shearwater in flight
because of its wedge-shaped tail.
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SHEARWATERS OF HAWAII
There are 50 to 60 kinds of shearwaters in the world. However,
only two or three kinds may be seen in Hawaii, wedge-tailed
and Newell's are the most common. The wedge-tailed shearwaters
in Hawaii are brownish-gray on their backs and tails and
light gray on their chests. This bird is about the size
of a pigeon. Wedge-tailed shearwaters can stay at sea for
years. Their webbed feet make it possible for them to kick
off from the surface of the water or from the crest of a
wave. Another special
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feature of these shearwaters is called the tube nose,
located at the base of the beak. The tube nose is connected
to a gland which removes extra salt from the bird's food
and water. It protects the nostrils from salty ocean spray
when the shear-waters fly near the water. The pointed beak
is also ideal for grabbing squid and small fish.
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FRIENDLY GUIDE FOR FISHERMEN
The wedge-tailed shearwaters are important to Hawaii's fishing
industry. Schools of tuna often force smaller fish and squid to
the surface of the ocean. The shearwaters gather to feed in these
areas. Fishermen know that where a lot of shearwaters are feeding
there might be a school of tuna nearby for them to catch.
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NEST-BUILDING ON THE GROUND
Wedge-tailed shearwaters nest on the ground. They often nest
in burrows, which are small caves two or three feet long. Sometimes
they nest in cracks between rocks, in rock piles, in low spots on
the ground or any place that gives them protection from the weather.
Most nests are sprinkled with a few pieces of grass or parts of
plants. The shearwaters begin courting and preparing their nestsin
April and May. They are "nocturnal in the colony," which means they |
| are more active at night dur-ing the nesting season.
The birds make a strange wailing or crying sound when settled in
the colony, so they are often called "the moaning birds." The shearwater
lays a single egg in June. Both adults share the job of incubation.
Each sits over the egg for about 10 days at a time, while the other
par-ent is feeding at sea. The chick hatches after about 52 days.
Both parents feed it partly digested food. |
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MIGRATION TO AND FROM HAWAII
When chicks are around three and one-half months old, the parents
stop feeding them. The chicks don't eat for about two weeks, as
they test their wings and learn to fly. When they fledge (have all
their adult feathers and can fly), the young birds learn to feed
themselves. In November the shearwaters migrate along the equatorial
countercurrent to the coast of Central America. They migrate back
to Hawaii in March; the cycle is repeated each year. |
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PROTECTING OUR SHEARWATERS
Because shearwaters nest on the ground, they are often attacked
by dogs, mongooses, rats and cats. For this reason, shearwaters
in Hawaii mostly nest on the small offshore islands, except on Kauai,
where they are still found on the main island. There are colonies
near Maui on Hulu Island and Molokini Island. Near Oahu, wedge-tailed
shearwaters are found on Manana Island, Mokulua and Mokumanu Island.
There may be a few small nesting sites on other islands. Kilauea
Point, Kauai, is the home of a large colony of these birds. At the
U.S. Fish & Wildlife Service Refuge there, they are protected from
their enemies by fences and trapping. At Kilauea Point from March
to November, you can get a close-up view of wedge-tailed shearwter
adults and chicks. |
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