Observing and photographing wildlife is a rapidly growing hobby that usually causes little disturbance or harm to animals. However, you should learn to view animals responsibly.
In most cases, the harm people cause wildlife is because of stress and energy the animal uses to move away from a perceived danger. This is particularly true in winter when animals tend to be concentrated in limited living space, and stress triggered by careless intruders can lead to a variety of dietary and health problems.
See the following pages for more information about wildlife viewing: