The term "co-nest" refers to the situation when two or more animals or birds share the same nest. Some antonyms of "co-nest" include "solitude," "loneliness," "individualism," and "exclusion." These terms describe situations where the animal or bird lives alone, away from any other animals, and doesn't share a nest with any other organism. "Separation," "isolation," and "detachment" are also antonyms of "co-nest" as they define the state of living apart from others or breaking away from a shared habitat. Another antonym for "co-nest" is "competitive," indicating an environment where animals or birds compete with each other for nesting space, food, or other resources.