The seasonal migration is a noteworthy characteristic. With the coming of spring, deer move upward from the lowlands, closely following the retreating snow. The young are born in late May or June, usually after the does have reached their summer range, although they may move higher to find relief from flies. There is practically no banding together of the deer at this time. Each mother and her offspring, usually twins, sometimes one and rarely three, comprise a family group, and tend to keep to themselves. The fawns are hidden at birth, and remain in some secluded spot until they are several days old. The mother visits them at intervals during the day so that they may be fed, and stays near their place of concealment. Almost every season “abandoned” fawns are discovered and brought in to one or another of the park’s ranger stations by well-meaning but ill-informed park visitors. In exceptionally rare instances the mother may have been killed by some predator or a passing automobile, but under no known circumstances has a fawn ever been deliberately abandoned. _Fawns, if found, should be left unmolested._ At the time of the spring migration to the uplands, the older bucks habitually move to higher levels than do the young bucks and does. They prefer the subalpine parks and meadows, and often range in pairs or in groups of from three to five or six individuals. [Illustration: New-born fawns, if found, should be left unmolested.] The first heavy snow starts the deer on their annual trek to the lowlands, and the journey is ordinarily a consistent one, once begun it is completed over a period of from several hours to a day or two, depending upon the distance to be covered. Study has revealed that deer follow regularly established routes during migration, returning year after year to the same general winter and summer ranges. Well-worn game trails along prominent ridges and watercourses are testimony to this concentrated movement, the intersecting minor paths are but tributaries to the major current of travel. It is prior to the fall migration that the deer herds assemble, the does, fawns, and yearling bucks banding together, the older bucks breaking away from their summer associations and joining the does for the mating season, which occurs in November and December. Vicious battles are frequent at this season. Determined to assert supremacy, the bucks are merciless antagonists, and at times the struggle is fatal to the loser. In rare instances both may perish, with antlers so tightly locked that escape for either is impossible, exhaustion and starvation the inevitable result. At the conclusion of the mating season the two sexes go their separate ways again, the bucks often assuming again the easy companionship of the summer months.