Grey-crowned cranes are, in common with other cranes, monogamous and appear to mate for life. During courtship they perform nuptial dances in which both birds participate. The display includes various bobbing and bowing actions as well as jumps. Either the male or the female can initiate the dance. It can begin in many different ways; the pair may be walking together nor not. The dance begins with a series of calls during which the gular sac is inflated. After which they both bob their heads, then spread their wings and begin a series of jumps. Either partner may call the display to a halt. (Johnsgard, 1983; Walkinshaw, 1973)
Grey Crowned Cranes require mixed wetland-grassland habitats. They typically nest within or on the edges of permanent or temporary marshes / wetlands (utilizing smaller wetlands than Wattled Cranes). They may also nest in well-vegetated farm dams, where they make their nests among tall, often reedy, wetland vegetation, often of a height so that the nest is sufficiently concealed from terrestrial predators. The breeding season of this species varies depending on the duration and intensity of local dry and wet seasons. In South Africa, the Grey Crowned Crane is a summer breeder, with a peak in egg laying around November / December.
Clutch size can vary from 2 to 4 eggs which is larger than other cranes that usually have a clutch size of 1 to 2 eggs. Newly laid eggs are a light blue. The eggs have an incubation period of 28 to 30 days. About 12 hours after hatching they are capable of swimming and float like little cork balls. They begin eating after 24 hours. By the second day of hatching they are able to wander with their parents in search for food and they return to the nest night for brooding.
After the chicks hatch the family group does not forage in the savanna but instead keeps to the marshland where the tall grass can provide maximum coverage. Chicks fledge between 56-100 days after hatching. The juveniles will then join a flock containing other juveniles. Juveniles reach reproductive maturity at around 3 years old. (Johnsgard, 1983; Walkinshaw, 1964; Walkinshaw, 1973;del Hoyo, et al., 1996
Their preferred foraging habitat consists of expanses of short to medium height open grasslands adjacent to wetlands where they feed on grass seeds, insects and other invertebrates. Grey Crowned Cranes also use agricultural lands extensively in which to forage, including pastures, irrigated areas, fallow fields, newly planted cereal crops and harvested fields where they feed on harvest leftovers. The Grey Crowned Crane’s generalist feeding strategy has allowed this species to adapt to human settlement and can be found most often in man-modified environments. Interestingly, the crowned crane is the most primitive of the living Gruidae. Primitive species of crowned cranes date back in the fossil record to the Eocene period (34 to 55 million years BME). Archaeologists discovered that at least eleven species of crowned cranes once existed in Europe and North America. Because crowned cranes are not cold hardy, it is believed they died out in these areas as the earth cooled, and only survived in warmer Africa.