Antigen: any foreign body that, once in the body, stimulates the production of an antibody. The coat of many bacteria and the structure of many toxin molecules are antigens. (https://www.fao.org/dairy-production-products/resources/glossary/en/?index=a)
Colonies of breeding animals, generally gregarious birds. The term is used for corvids and the breeding grounds of colony-forming seabirds, marine mammals (true seals and sea lions), and even some turtles. (Adapted from https://en.wikipedia.org/wiki/Rookery)
Note
Some pinnipeds use terrestrial sites for reproduction, resting, molting, and other activities. Rookeries are terrestrial sites used for mating, giving birth, and resting. Rookeries are primarily used during breeding season but can be occupied at other times of the year as well. Haulouts are terrestrial sites used for resting anytime of the year.
