Northern harriers (marsh hawks) are valuable rodent hunters. Preferred habitat consists of marshes at all elevations. The hawks prefer hunting live prey including: small mammals, birds, amphibians, reptiles, and some insects. Nests are constructed with sticks and grasses either on the ground or in low vegetation. Mating takes place in early April and nesting by early May. The young hatch in June after a 31-32 day incubation period. They are fledged at 30-35 days of age. The population trend of the northern harrier is stable.