Their warm, thick under covering of fine wool protects them from the coldest blasts. During storms the sheep commonly huddle together to the leeward of a cliff. Sometimes they stand thus for days and are completely drifted over. At the close of the storm the stronger ones lead and buck their way out through the snow. Occasionally a few weak ones perish, and occasionally, too, a mountain lion appears while the flock is almost helpless in the snow. Excursions from their mountain-top homes are occasionally made into the lowlands. In the spring they go down early for green stuff, which comes first to the lowlands. They go to salt licks, for a ramble, for a change of food, and for the fun of it. The duration of these excursions may be a few hours or several days. Most of the time the full-grown rams form one flock; the ewes and youngsters flock by themselves. Severe storms or harassing enemies may briefly unite these flocks. One hundred and forty is the largest flock I ever counted. This was in June, on Specimen Mountain, Colorado; and the sheep had apparently assembled for the purpose of licking salty, alkaline earth near the top of this mountain. Wild sheep appear to have an insatiable craving for salt and will travel a day's journey to obtain it. Occasionally they will cross a high, broken mountain-range and repeatedly expose themselves to danger, in order to visit a salt lick. The young lambs, one or two at a birth, are usually born about the first of May in the alpine heights above timber-line. What a wildly royal and romantic birthplace! The strange world spreading far below and far away; crags, snowdrifts, brilliant flowers,--a hanging wild garden, with the ptarmigan and the rosy finches for companions! The mother has sole care of the young; for several weeks she must guard them from hungry foxes, eagles, and lions. Once I saw an eagle swoop and strike a lamb. Though the lamb was knocked heels over head, the blow was not fatal. The eagle wheeled to strike again, but the mother leaped up and shielded the wounded lamb. Eaglets are occasionally fed on young lambs, as skulls near eagle's nests in the cliffs bear evidence. A number of ewes and lambs one day came close to my hiding-place. One mother had two children; four others had one each. An active lamb had a merry time with his mother, butting her from every angle, rearing up on his hind legs and striking with his head, and occasionally leaping entirely over her. While she lay in dreamy indifference, he practiced long jumps over her, occasionally stopping to have a fierce fight with an imaginary rival. Later he was joined by another lamb, and they proceeded to race and romp all over a cliff, while the mothers looked on with satisfaction. Presently they all lay down, and a number of magpies, apparently hunting insects, walked over them.