The survival and well-being of Monarch butterflies depends on several factors. While the adults feed on nectar from a variety of flowers, the larvae feed only on milkweed. Therefore, adequate flowers and milkweed are necessary for the Monarch's life cycle. Habitat loss and herbicides are threats to the survival of many plants and animals including the Monarch. In addition to its summer habitat, the migrating generation must also have trees to roost on at the overwintering sites. These areas are also threatened by development. Several conservation groups (see resource list) are working to protect the Monarch's habitats.