kiwi birds

Kiwis, or wingless birds[4], are flightless ratites. They are small in size, about the size of a common chicken. They exhibit sexual dimorphism: females are larger than males. Kiwis have a pear-shaped body, a small head, and a short neck. They weigh between 1.3 and 4 kg.

The kiwi has the most reduced wings of any living bird: at only 5 cm long, they are almost invisible among the plumage. However, the kiwi retains the habit of tucking its bill under its wing when resting. The bird's body is uniformly covered with soft, gray or light brown feathers, more like fur. It has no tail. The legs are four-toed, short, but very strong, with sharp claws; their mass accounts for approximately one-third of the bird's body weight. The skeleton is not pneumatic: the bones are heavy and lack air pockets.

Kiwis rely primarily on their hearing and smell rather than their sight—their eyes are very small, only 8 mm in diameter. Among birds, only some species of American vultures, particularly the yellow-headed vulture, have a more powerful sense of smell. Kiwis have a very flexible, thin, straight or slightly curved bill, which reaches 95–105 mm in length in males and 110–120 mm in females. Kiwis' nostrils open at the tip of the bill (in other birds, at the base). The tongue is reduced. Vibrissae, or tactile hairs that sense movement, are located at the base of the bill.

The normal body temperature of a kiwi is 38°C, which is two degrees lower than that of other birds and closer to the body temperature of mammals.

Kiwi feathers emit a strong, specific smell, reminiscent of mushrooms, which makes the birds vulnerable in modern conditions: ground predators that have appeared in New Zealand easily find them by smell[2][4].