Gruiformes are mostly ground-living birds, nesting in grasslands, marshes, and forests. On the ground, they are vulnerable to predators. Stoats introduced from Britain to New Zealand in the 1800s nearly wiped out the native takahe (Notornis mantelli). Impacts to grasslands, such as mechanical hay harvest, also destroy nests. European colonization of the U.S. was a disaster for whooping cranes (Grus americana). Hunting and agriculture reduced a thriving population of more than 10,000 to only 15 cranes. Conservation actions such as captive rearing have helped many gruiformes. The whooping crane population has increased to several hundred individuals, thanks to clever ideas such as using ultralight planes to teach migration routes to young birds. However, crane populations continue to be threatened by collisions with power lines, shooting, and predators. Several other crane species are listed on the "IUCN Red List of Threatened Species". Cranes are a symbol of good luck in Asian countries, but may need some good luck themselves to survive in the future.

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).