As temperatures rise and valley snow melts, the exposed vegetation becomes green, and new plants sprout. This new plant growth provides essential nutrition, helping the animals of Grand Teton replenish their depleted energy reserves lost during winter.
● The emergence of spring vegetation is especially vital for pregnant ungulates, whose nutritional needs increase as they prepare to give birth in the next two months. Gestation periods in mammals are consistent with calving seasons occurring on schedule, regardless of weather. The first bison calves of the year are born in early April, while moose and elk calves arrive in May.
● The northern migration of elk from the National Elk Refuge into Grand Teton National Park has begun. Elk follow the snow melt along river banks and east-facing slopes that melt first. Typical migration patterns trace initial elk movement into the Snake River corridor, just north of park headquarters in Moose.
● With the snowpack receding quickly on the valley floor and rivers opening up, some bald eagles are already sitting on their nests. Other early-season nesters like ravens, golden eagles, great-horned owls, and Canada geese have begun courtship and breeding activities.
● Migrating birds are arriving daily including western bluebirds, red wing blackbirds, meadowlarks, osprey, red-tailed hawks, northern flickers, and robins. The first sandhill cranes have arrived announcing and strengthening their pair bonds through calls and courtship dances!
● Sage grouse numbers at their lek (mating) sites will likely peak at the end of April or the first part of May.
● In the coming weeks, snowshoe hares and long-tailed weasels will begin to shed their white winter fur trading it for the browns that better camouflage their summer activities.
● Bears are out in increasing numbers. They are looking for winter-killed carcasses, leftover berries, pine seeds, and new vegetation to feed on during the spring months. Be sure to carry bear spray when traveling throughout the ecosystem.
● Wolves, coyotes, and foxes localize their hunting activity near their den sites to facilitate tending to newborn pups and kits.
● Melting pond ice means that beaver activity is ramping up. Spring marks the start of their courtship and breeding season. Beavers mate for life and form a strong pair bond within their family unit. Litters of two to four babies, called kits, are born between April and July. In the spring, beavers work non-stop to build and maintain their dams and forage for newly sprouted plants and fresh tree bark. Young adult beavers, 2–3 years old, disperse away from their colonies to establish their own territories, build new lodges, and find mates.
● In early spring Teton bighorn sheep move from their high-elevation winter ranges to mid-elevations in order to access nutritious vegetation green-up.
● Moose with a ghost-like appearance due to patchy hair loss suffer from winter tick infestations. These ticks latch onto moose by the thousands in the fall and feed there for months. The moose’s attempts to rub the ticks off results in patches of broken hair or bare skin. Tick infestations can cause moose deaths, especially in young moose.
