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.
Hummingbirds are small, colorful birds with iridescent feathers. Hummingbirds primarily eat flower nectar, tree sap, insects and pollen. The hummingbirdâs fast breathing rate, fast heartbeat and high body temperature require that they eat often. They also require an enormous amount of food each day. Hummingbirds have a long tongue which they use to lick their food at a rate of up to 13 licks per second.