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.
Of course, nectar, honey, sugar, and insects arenât the only things hummingbirds consume. Some hummingbird stomachs were also shown to contain grains of pollen. The stomachs of two blue-throated hummingbirds examined by biologists Clarence Cottam and Phoebe Knappen included 10 percent and 15 percent pollen.