Balearica regulorum [bal' ih ar' ik uh reg yoo' lor um]

Description

This colorful crane is easily recognized by its large yellow crown, each feather of which is tipped with black. Another distinguishing feature is the white cheek patch with a reddish tint. Black feathers surround the cheek patches at the base of these feathers. At the bottom of the chin there is a red gular sac (similar to a wattle, but inflatable). The neck feathers as well as most of the body feathers are a pearly grey, the wings are mostly white but can have feathers that range in color from brown to gold, the tail is black, and the upper coverts are a pale straw-like yellow. The short bill is gray and the legs are black. This crane is also notable for being one of only two crane species capable of perching in trees, thanks to a long hind toe (the other is the black crowned crane).

Juveniles are generally grey with a brown crown and nape. Their irises tend to be brown. The gular sac that usually appears after four months is pink and as the crane matures gains the red coloration. Adult plumage is usually gained after 12 months.

Both sexes af breeding adults are similar in coloration, but the male is slightly larger. They weigh between 6.6 and 8.8 pounds, and are 39-43 inches in length, with wingspans of 70-79 inches.

Distribution and Habitat

East African crowned cranes (B.r. gibbericeps) are found in Uganda and Kenya to Northern Zimbabwe and Northern Mozambique. South African crowned cranes (B.r. regulorum) are found in southern Angola and North Namibia east through Botswana to Zimbabwe and south to South Africa.

Both subspecies are usually found in grasslands close to bodies of water, preferring to nest near bodies of water that provide cover, but can also be found in agricultural lands such as pastures, cropland, or fallow fields. In the south they are also found in shallow intermittent or seasonal lakes. They generally select habitats that include some trees.

Diet

Grey crowned cranes eat insects, small animals such as lizards and worms, and seeds. They often utilize disturbances by other species in foraging for insects. They also feed on newly plowed fields, and have been observed eating maize directly from the cob, knocking out kernels, instead of eating the kernels found scattered around.

Reproduction

Grey crowned cranes appear to mate for life.

Either the male or the female can initiate the "courtship dance." It can begin in many different ways, and the pair may or may not be walking together prior to its start. 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.

The breeding season varies with the rains. In east Africa it appears to be year round with peaks in the wetter periods. In South Africa and in drier regions, breeding mainly occurs during the rainy periods of October through April, with peaks between December and February.

The usual location for a nest is in standing water or quite near it. Grey-crowned cranes also select areas to nest where there is an abundance of tall vegetation. The vegetation provides cover but allows the crane maximum visibility with only it head showing. Both sexes cooperate in the building of the nest, which usually consists of uprooted grasses arranged to create a circular platform up to 34 inches in diameter about 3 feet above water level. However, the grey crowned-crane will occasionally nest in trees.

Clutch size can vary from 2 to 4 eggs, which is double the size of other cranes. Newly laid eggs are a light blue. Incubation duties are shared by both parents, and lasts 28-30 days. Like many cranes, grey crowned chicks are precocial, capable of swimming about 12 hours after hatching. They begin eating after 24 hours, and by the second day of hatching they are able to wander with their parents in search for food. The family group does not forage in the savanna but instead keeps to the marshland where the tall grass can provide maximum coverage. Parents tend to the young until they fledge at 56 to 100 days. The juveniles will then join a flock containing other juveniles.

Sexual maturity is reached at about 3 years, and grey crowned cranes can live 22 years in the wild.

Other Information

Grey crowned cranes are very territorial when it comes to nesting sites, but when it comes to foraging sites there have been no observations of a territorial display. They have two different displays when dealing with possible threats: a distraction display and an attack display.

Grey crowned cranes are listed as endangered, due primarily to habitat loss.

Scientific Classification

phylum Chordata
subphylum Vertebrata
class Aves
order Gruiformes
family Gruidae
genus & species Balearica regulorum

INTERNET SOURCE
Animal Diversity Web http://animaldiversity.org/accounts/Balearica_regulorum/

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SKC Films Library > Science > Zoology > Birds > Order Gruiformes

This page was last updated on January 14, 2017.