NATIONAL PARK SERVICE Wildlife Portfolio of the Western National Parks

THE KAIBAB SQUIRREL is one of the rarest mammals in the national park system. It is found on the Kaibab plateau, on the North Rim of the Grand Canyon, and is native to no other part of the world.

Near Bright Angel Point I found a Kaibab squirrel running about on the ground in a grove of quaking aspen. I followed this little animal for nearly a quarter of a mile until it reached its "nest" tree. The nest was built in the fork of a large bushy western yellow pine about 40 feet above the ground. Here the squirrel had garnered and piled a large quantity of dry branches of the yellow pine to form a nest approximately 2-1/2 feet in diameter by 3 feet in height. I noticed, while this squirrel was up in the tree, its long white tail waved like a pendulum below the limb on which it was sitting. At other times it remained motionless and hid by crouching lengthwise of the limb with its tail tightly pressed against its back. It is believed that the tail, when thus held over the back, helps to conceal the animal when viewed from above, as by a hawk.

The young squirrels are born in a small central chamber of this bulky nest during the latter part of June. The litters are known to vary from two to six. Only one brood is born each year.

Kaibab squirrels are much quieter than gray squirrels; also, in going from tree to tree, the Kaibabs travel more on the ground instead of from limb to limb like the gray squirrels.

The Kaibab squirrel lives almost exclusively on the cambium layer of the second year growth of the yellow pine. Only the terminal twigs of vigorous healthy yellow pine are chosen and the rough outer bark is removed to reach this cambium layer. I have counted the remains of more than 500 of these terminal twigs, about the size of a lead pencil and from 4 to 10 inches in length, on the ground beneath one tree.

Goshawks are believed to be the outstanding enemies of the Kaibab squirrel. Coyotes also catch a few of these squirrels each winter.

While this squirrel feeds, its tail is curled up over its back in characteristic fashion. (See illustration.) This posture reveals that the tail is white all around. Because of this, the Kaibah squirrel is known locally as the "white-tailed" squirrel.

Since the Kaibab squirrel is unique and has a restricted range, the National Park Service, the United States Forest Service, and the State of Arizona have entered into a cooperative agreement whereby the animal is given strict protection. It is hoped that success will follow this effort to preserve this unique species for the enjoyment of future generations.

PHOTOGRAPH, GRAND CANYON, ARIZONA, JUNE 2, 1930.