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.
Hummingbird Feeders. Hummingbirds get the energy they need to maintain their astonishing metabolism primarily from flower nectar and the sugar water they find at feeders (here's the recipe). Think of them as miniature flycatchers, and sugar is just the fuel for getting their real nourishment.