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.
Feeding Habits - What Bluebirds Eat. When it comes to feeding, what Bluebirds eat is a large amounts of insects. Eighty percent of their diet comes from insects during spring and summer. In addition to insects, these birds eat berries and fruits off of small trees and shrubs.