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Thursday, Dec. 23, 2004

ANIMAL TRACKER

Rock ptarmigan


PHOTO COURTESY OF BIO-IMAGE NET

* Japanese name: Raicho
* Scientific name: Lagopus mutus
* Description: Ptarmigan are medium-size, plump birds about 35 cm long with a 54-60 cm wingspan. They weigh around 500 grams. Since the birds depend on camouflage for defense, their plumage changes with the season. In summer, the top half is a subtle mixture of gray, brown and black, while the belly and wings are white. The top of the head has a red cap. In winter, the bird becomes white all over, apart from its tail and eye-patch, which stay black. The ptarmigan has a harsh voice, producing a rasping croak. The alarm call is a grating sound. Perhaps because of this, it is called "thunder-bird" in Japanese.
* Where to find them: Year-round, in arctic landscapes, high in the mountains across central Japan. Ptarmigan trail their feet in soft snow, so their tracks may be seen even if the bird is not. In very cold weather, they may move to the edge of forests to stay warm.
* Food: In winter, catkins, leaves and leaf buds, overwintering berries and insects. In summer ptarmigan eat shoots, caterpillars and beetles.
* Special features: After a winter of huddling together and foraging for food, when the snow melts ptarmigan start looking for mates. Males become boisterous and intolerant of potential mating rivals. They defend territories by gargling, screeching and even flying at intruders. Mating takes place in spring and females lay six to 10 eggs, which are incubated for three weeks. The chicks hatch May-June and, despite the fact that the male provides no help rearing or feeding them, they grow extraordinarily quickly. Only nine-10 days after hatching, the chicks can flap their wings hard enough to clear the ground; by eight weeks they have primary flight feathers and can fly well. Nesting on the ground means that they are vulnerable to many predators, so selection has led to an accelerated development time to try to minimize the vulnerable stage. Nevertheless, ptarmigan are still vulnerable to the weather and population numbers can vary wildly from year to year, according to the severity of the winter.



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