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.
A good guideline of when to stop feeding hummingbirds is to leave your Hummingbird feeder up for about 2 weeks after your Hummingbirds have left for the season. This will provide nectar for any Humming birds that might have gotten a late start on their southward migration due to illness, injury or other reasons.