Gallinaceous birds (also known as game birds) spend the majority of their time on the ground, using their feet to scratch for seeds, fruit, and insects. Although their plumage tends to be mottled brown, providing camouflage, they are an attractive meal for terrestrial predators like raccoons and foxes. Their best defenses are their enlarged flight muscles, giving them the ability to take off in a hurry. Those same enlarged muscles are what make chicken breast a substantial meal for humans. But gallinaceous birds reserve flight for real emergencies, usually first running from danger on their strong legs. If running away is not enough, they burst off the ground in nearly vertical flight. When threatened, a gallinaceous bird communicates it with body language. Picture the puffed out chest and raised head of an angry chicken.

Many male birds use brightly colored feathers to show off to females during the breeding season. Most males set up territories containing important resources (food, nesting materials), and try to attract females while keeping males out. Courtship can be an elaborate affair, with displays by the male and sometimes by females, depending on the species. After mating, all birds lay eggs. As the egg develops, the yolk gets covered with layers of egg-white (to feed the embryo), shell (for protection), and pigment (for color). Eggs must stay at the right temperature for development. Most birds incubate their eggs by sitting on them so that they touch a warm, bare spot of skin on the parent (brood patch). Parental care of hatchlings tends to be intensive, with one or both parents feeding the young. Hatchling birds have a lot to learn (the parents' song, the location of feeding areas, migration routes).