Colorado Parks and Wildlife officials are warning the public across the state to be mindful of potentially aggressive behavior from wildlife defending their young. 

Through the end of June, Colorado Parks and Wildlife’s annual advisory asks people to avoid elk, moose and deer that have newborn calves and fawns this time of year. Two encounters with cow moose — including one in Breckenridge — resulted in injuries to people who got too close to the moose’s calves. Owners are also encouraged to keep dogs on leashes at all times, since dogs are more likely to trigger aggression.

One way to avoid an unnecessary run-in with a moose is to steer clear of willow habitats near rivers where they are likely to be found eating or resting. Their calves, born from the end of May to mid-June, are often lying in the willows while their mother is off grazing. Calves, which weigh 26 to 28 pounds at birth, typically gain about 2 pounds of weight per day, reaching weights of 385 to 400 pounds by October.

Elk calves are typically born in locations where cover, forage and water are in juxtaposition in late May or early June. Calves weigh between 28 to 35 pounds at birth and are covered with small white spots for the first few months of their lives.