The Kori Bustard, Ardeotis kori, is the heaviest bird in the world capable of flight and resides in African savanna and grassland ecosystems. This large, non-migratory, ground-dwelling species has an exceptionally varied diet. As an opportunistic omnivore, its menu is determined by the food sources most readily available, allowing it to thrive across habitats from semi-arid scrublands to open woodlands.
The Omnivorous Menu: Main Dietary Components
The majority of the Kori Bustard’s energy intake comes from animal protein, with a strong preference for invertebrates. Its diet is heavily focused on large insects, particularly during peak seasons of abundance. Specific examples include grasshoppers, locusts, beetles, termites, armoured ground crickets, and dung beetles.
The bustard also readily consumes a variety of small vertebrates when the opportunity arises. These prey items include lizards, snakes, small rodents, and the eggs or nestlings of other ground-nesting birds. The consumption of carrion provides an additional source of animal protein.
Plant matter forms a supplementary, yet important, part of the diet, especially when animal prey is scarce. This includes a variety of seeds, berries, flowers, and green shoots. The bird actively digs for subterranean plant parts like roots and bulbs. A unique component is the hardened sap, or gum, from Acacia trees.
Hunting and Foraging Strategies
The Kori Bustard is primarily a terrestrial forager, spending most of its time walking slowly and deliberately across open ground while scanning for food. The bird utilizes its keen eyesight to detect the slightest movement of prey in the low vegetation. Once a potential meal is spotted, the bustard relies on stealth, moving slowly to approach the item before striking quickly.
This foraging method is opportunistic, and the bustard often capitalizes on disturbances in the environment. They are known to follow grazing herds of mammals, such as zebras and antelopes, to capture the insects flushed out by the larger animals’ hooves. The birds are also drawn to bush fires, where they consume the insects and small animals that are killed or disturbed by the flames.
Kori Bustards have been observed in a mutualistic association with species like the Carmine Bee-eater. The smaller birds will perch on the bustard’s back and capture the insects that the large bird’s movements stir up from the grass.
Adapting the Diet to Environmental Changes
The Kori Bustard’s ability to survive in its semi-arid habitat is linked to the flexibility of its omnivorous diet, which shifts significantly with seasonality. During the wet season, when insects are abundant and reproduce rapidly, the bird’s diet is heavily skewed toward animal matter. This high-protein intake supports breeding activities and general vigor.
Conversely, during the dry season or periods of drought, the population of invertebrates declines sharply. The bustard then increases its reliance on plant matter, such as roots, bulbs, and the gum from thorn trees, to sustain itself. This dietary shift is facilitated by the bird’s well-developed caeca, specialized sections of the large intestine that aid in the digestion of fibrous plant material.
This adaptation also plays a role in the bird’s hydration, as the Kori Bustard is not dependent on frequent visits to open water sources. The moisture contained within its food, particularly from succulent plants and the body fluids of its prey, is often sufficient to meet its needs. The species will drink when water is available, but the flexibility of its diet allows it to make nomadic movements in response to localized rainfall and food supply.