The pigeon, originally native to Eurasia, has now been introduced World Wide. The pigeon has adapted to life along side humans very well and can be found in most modern cities. Introduced pigeon populations have caused declines in native bird species due to competition. Today, the pigeon is kept as a pet and is hunted for sport and food, but is generally considered a pest by most of humanity.
Sclerotic rings are rings of bone found in the eyes of several groups of vertebrate animals, except for mammals and crocodilians.
- Includes a pair of eye rings