Stanley crane, Paradise crane, Blue crane, Stanley crane, Paradise crane
The blue crane (Grus paradisea ), also known as the Stanley crane and the paradise crane, is the national bird of South Africa. The species is listed as Vulnerable by the IUCN.
The Blue crane is South Africa's national bird. It is small in relation to other cranes and has a large head, a thick neck, and beautiful long wing feathers, called tertials, that trail behind it and can be mistaken for tail feathers. It has head feathers that can be erect when it is excited or aggressive. Males and females have similar plumage but males are larger. The juvenile is a pale gray color and does not have elongated tertial feathers. Chicks have dark gray bodies and brown heads. Their feet and legs are black.
Blue cranes are native to southern Africa, with more than 99% of them living within South Africa. There is a small breeding population in and around the area of the Etosha Pan in northern Namibia. These birds breed at high elevations in dry grasslands where there is less chance of disturbance. They roost and breed in wetland areas if these are available, some individuals prefer to nest in arable land and pastureland. Blue cranes migrate locally, moving with their chicks in autumn and winter to lower elevations.
Blue cranes are more terrestrial than other large cranes. Their shorter bill is an adaptation to their feeding behavior, as they feed more often in grassland areas than in wetlands. Blue cranes are territorial and solitary breeders, however, after the nesting season, the birds become highly congregation and may gather in flocks of up to 1,000 individuals. They also prefer to roost at night communally. There is a strict hierarchy in groups, with the larger adult males being dominant. All cranes dance, with movements including bowing, jumping, running, grass or stick tossing, and the flapping of wings. They dance at any age, and although dancing is commonly associated with courting behavior, it is generally thought to be a usual part of a crane's motor development and serves to deal with aggression, relieve tension, and make the pair bond stronger.
Blue cranes are herbivores (graminivores) and carnivores (insectivores). Most of their diet consists of grasses and sedges, with many types fed on based on their proximity to the nests. They also regularly feed on various insects such as grasshoppers. Small animals such as crabs, snails, frogs, small lizards, and snakes may supplement the diet, with such protein-rich food often being broken down and fed to the young.
Blue cranes are monogamous with long-term pair bonds. Courtship involves a dance where the male bird chases the female, interspersed with bows, leaps, and bouts of calling. From September to February is the usual nesting time, with the typical nesting site being at high elevations amongst secluded grassland. The eggs are laid on bare ground or in the grass. Two eggs are laid and incubation lasts around 30-33 days, carried out by both parents. The young are able to walk after 2 days and can swim well shortly thereafter. They are fed primarily by their mothers, who regurgitate food into their mouths. The chicks fledge at the age of 3-5 months and continue to be tended to until the next breeding season, at which time they are chased off by their parents. They will gain reproductive maturity at 3-5 years old.
The biggest threat to these beautiful birds is habitat destruction by converting natural biomes to agricultural land. As humans continue to increase in number, agricultural expansion, persecution, disturbance, and the grazing of livestock also intensify, and these threats will probably become worse. Other threats are colliding with power lines, predation by dogs, and illegal capture of chicks for the pet trade and for food.
According to the IUCN Red List, the total population size of the Blue crane is 25,550-45,132 individuals (here rounded to 25,000-46,000 individuals); this is assumed to equate to roughly 17,000-30,000 mature individuals. Currently, this species is classified as Vulnerable(VU) on the IUCN Red List and its numbers today are decreasing.