Both adults and young have the ability to enter a sort of torpid state to overcome periods of food shortage caused by inclement weather. Adult Hummingbirds feed every 15-20 minutes during the day unless migrating when they tend to survive on stored fat reserves. Hummingbirds are aggressive birds which in some cases defend territories even outside of the breeding season. They will defend their territory or a good flower patch not only from other Hummingbirds but also from birds of a much larger species, even hawks. They can get away with this because of their manoeuvrability in the air is far greater than the larger birds.
Hummingbirds have two main feeding strategies.
One is to maintain a territory containing good nectar sources and defend this against all comers. The second strategy involves trap-lining patches of high reward flowers. This means the bird will have a flight route that takes it from one patch of flowers to the next which it can travel several times a day. In this way the flowers can load a new supply of nectar between visits. Some species of flowers with a distribution along a northwards transect in the USA come into flower in harmony with a migrating Hummingbird species, so as the bird travels north it always has food available and the flowers always have a dedicated pollinator each spring.