The White-throated needletail (Hirundapus caudacutus), also known as needle-tailed swift or spine-tailed swift, is a species of large swift in the Apodidae family. It is commonly reputed to reach speeds of up to 170 km/h (105 mph), though this has not been verified. These birds have very short legs which they use only for clinging to vertical surfaces. They build their nests in rock crevices in cliffs or hollow trees. They never settle voluntarily on the ground[citation needed] and spend most of their lives in the air, living on the insects they catch in their beaks.