Physical characteristics: The variable oystercatcher is about 18.5 to 19.3 inches (47 to 49 centimeters) in length. Males weigh about 1.5 pounds (678 grams) while females are a little heavier at 1.6 pounds (724 grams). The variable oystercatcher is the only species that includes all black individuals as well as black-and-white colored individuals. Some individuals have a coloration that is intermediate between the two primary types. They are known as "smudgies." The eye, eye ring, and bill are all red in this species.
Geographic range: The variable oystercatcher is found exclusively on the coasts and islands of New Zealand.
Habitat: Variable oystercatchers occupy rocky and sandy seashore areas.
Diet: Variable oystercatchers eat primarily marine invertebrates such as bivalves, crabs, snails, and polychaetes (PAHL-ee-keets; marine worms).
Behavior and reproduction: Variable oystercatchers are territorial, but occasionally form flocks. There is frequent breeding between differently colored variable oystercatchers. The breeding season occurs in December and January. Nests are built on beaches and sand dunes. Females typically lay three eggs which hatch after twenty-five to thirty-two days.
Variable oystercatchers and people: No significant interactions between variable oystercatchers and people are known.
Conservation status: Variable oystercatchers are not officially considered threatened at this time. However, the total population is only about 3,900 individuals. Variable oystercatchers have been affected by human disturbance and predation by introduced mammals. ■
FOR MORE INFORMATION Books:
BirdLife International. Threatened Birds of the World. Barcelona: Lynx Edicions, 2000.
del Hoyo, J., A. Elliott, and J. Sargatal, eds. Handbook of the Birds of the World. Vol. 3, Hoatzin to Auks. Barcelona: Lynx Edicions, 1996.
Perrins, Christopher, ed. Firefly Encyclopedia of Birds. Buffalo, NY: Firefly Books, 2003.
"Family Haematopodidae (Oystercatchers)." Animal Diversity Web. http://animaldiversity.ummz.umich.edu/site/accounts/classification/ Haematopodidae.html#Haematopodidae (accessed on April 22, 2004).
"Haematopodidae (Oystercatchers)." The Internet Bird Collection. http:// www.hbw.com/ibc/phtml/familia.phtml?idFamilia=55 (accessed on April 22, 2004).
"Oystercatchers." Bird Families of the World, Cornell University. http://www.es.cornell.edu/winkler/botw/haematopodidae.html (accessed on April 22, 2004).
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