THE CATTLE EGRET
Vistors to Hawaii often ask, "What is the name of that white
bird with the long slim neck and long legs that we see in
the fields be mowed and sitting on the backs of cattle?" The
answer to that question is the cattle egret. The egret, a
member of the heron family, is about 20 inches long and weighs
about four ounces. Young birds have dark green legs. Adults
have yellow beaks and legs. During breeding sea-son the legs
and beak turn pink, and reddish-brown feathers appear on the
breast and top of the head. |
 |
ORIGIN AND DISTRIBUTION
Cattle egrets are natives of Spain, Asia and Africa. In the
late 1800s they made their way to South America. They now
inhabit large areas in the United States and can be seen as
far north as Canada. In fact, egrets are found on every continent
in the world except Antarctica. Cattle egrets were intro-duced
in Hawaii in 1959 by the State Board of Agriculture and Forestry.
Local ranchers provided funds, hoping the egrets would control
flies and other insect pests which bothered cattle. The birds
were brought from Miami, Florida to Honolulu, then quarantined
and tested to be sure they were free of disease. The first
25 egrets were released at Kipu Ranch, Kauai on July 17, 1959.
A total of 105 egrets were released in 1959 at Parker ranch,
Hawaii; Puunene, Maui; Molokai Ranch; Kualoa Ranch of Oahu
and at the Honolulu Zoo. |
NESTING AND BREEDING
Cattle egrets are colonial nesters - they nest in groups or
colonies ranging in size from a few pairs to several thou-sand
birds. The nesting colonies are also called rookeries. The
male egret attracts the female to his territory with bill-clapping,
calls, dancing and stretch-ing motions and by making his "red
dirt" colored head plumes stand up. The male usually
brings sticks, branches and grass to the nesting site. The
female arranges a nest about a foot in diameter, built up
off the ground, and lays two to five blue-green eggs. Chicks
hatch after 22-26 days. They begin to leave the next 20 days
later and are independent 45 days after hatching. |
FEEDING
Egrets feed in both open, dry areas such as pasturelands,
and in wetlands. Cattle egrets are opportunistic feeders -they
follow herds of cattle, eating insects on and around them.
They also feed where tractors, mowers and other machines make
food easy to find. Cattle egrets eat great quantities of insects
such as grasshoppers, cockroaches, caterpillars, flies, moths
and centipedes. They also eat crabs, mice, frogs, skinks and
lizards. |
 |
| After feeding, cattle egrets can be seen returning
to their rookeries each evening in flocks of up to 20 birds. |
ADAPTATION IN HAWAII
Cattle egrets have adapted very successfully to life in the
Hawaiian Islands. They feed in pastures and in wetlands and
help control insect and rodent pests. As the number of cattle
egrets increase, some problems are seen. Egrets also feed
on shrimps and fish in aquaculture ponds, and on endangered
wetland birds (coots, moorhens, stilts, ducks). They can be
a health hazard, since they often feed at landfills and dumps.
Cattle egrets both eat and com-pete for food with other useful
insectivo-rous (insect-eating) feeders such as frogs, toads
and skinks. |
OBSERVATION
Watch a cattle egret feeding. Can you tell when the bird is
eating a centipede? Many agricultural workers who see egrets
daily claim the bird shakes its neck violently as the centipede
goes down its throat, biting all the way! |
|
|
