Torea
and Torea-pango, the oystercatchers
Haematopus unicolor and Haematopus ostralegus
Click
on the picture to
hear
the Oystercatcher
Around
Ohiwa Harbour here, the oystercatchers are a constant source of interest
and delight. Unlike the South Island pied oystercatcher, the variable is
here all the year around and though it flocks together with the SIPOs at
the roosts during the winter it is most often seen in pairs around the
harbour's edge and even on the beach at Ohope.
The oystercatchers are
the workers of the beach and mudflats, constantly busy and on the hunt
for food while the gulls hang around in gangs looking for the main chance.
They are noisy and talkative birds, feeding on molluscs, crabs and worms.
They open bivalve shellfish by stabbing between the shells and twisting
the bill to part the shells or by hammering a hole in the shell. The adults
spend some time teaching their offspring the trick of opening shells, a
constant source of amusement. They are great parents and are aggressive
towards any threat to their offspring, mobbing aerial predators and leading
ground predators (including humans) away with various tactics.
The pied oystercatcher
breeds inland on river beds and farmland, mainly in the South Island and
migrates north to estuaries in autumn and winter. The variable breeds on
rocky and sandy coasts and stays in its territories all the year round.
The variable is slightly larger. In its variable phase is usually identified
from the pied by the lack of a white tab in front of the folded wing, an
exercise for birdwatchers.
Oystercatchers are
found on every continent except Antarctica. In South America the Falkland
Islands, New Zealand and Australia one of the pair of species is pied the
other black. There is still no uniform agreement on how many species of
oystercatchers there are. Sibley & Monroe (1990) and Clements (1991)
lists 11 species. Hockey (1996) includes the South Island Oystercatcher
H. finschi within the races of the Eurasian Oystercatcher H. ostralegus,
but splits off the "Chatham Oystercatcher" H. (u.) chathamensis from the
Variable, creating thereby an endangered species. He also gives some arguments
why the Sooty Oystercatcher H. fulginosus of Australia should be split
into two species (creating the "Spectacled Oystercatcher" H. opthalmicus)
and why the Galapagos Is. birds (galapagensis) should be separated from
the American Oystercatcher.
credit for image, Bert
Lee