Causes and symptoms. Fatigue may be the result of one or more environmental causes such as inadequate rest, improper diet, work and home stressors, or poor physical conditioning, or one symptom of a chronic medical condition or disease process in the body.
1 A hummingbird will use its tongue to lap up nectar from flowers and feeders. 2  A hummingbird's tongue is grooved like the shape of a W. 3  Hummingbirds have tiny hairs on the tip of the tongue to help lap up nectar.
In the summer, even though there is a lot of food available for birds, their energy requirements are high because they must feed their young. Here at the Treman Bird Feeding Garden at the Cornell Lab of Ornithology, we keep our feeders filled year-round for the benefit of the birds and the pleasure of our visitors.Whether or not you do too is up to you! To ensure a safe bird-feeding environment, change hummingbird nectar every three days.. Like the other birds, the hawk is coming to your yard because there is a source of food. If you want to discourage the hawk, you'll have to take your feeders down for a few days to disperse the hawkâs food source--smaller birds.