The kiwi is the flightless, nocturnal national bird of New Zealand, where it is endemic. This ground-dwelling species evolved to occupy a specialized niche in the absence of mammalian predators. Its omnivorous diet reflects this lifestyle, consisting of both animal and plant matter found primarily on or beneath the forest floor. A consistent reliance on subterranean prey defines its feeding habits.
Primary Invertebrate Food Sources
The bulk of the kiwi’s diet consists of invertebrates found underground, providing the most significant source of protein and moisture. Earthworms are the staple food item; some native New Zealand species can exceed half a meter in length. These worms are highly hydrating, consisting of approximately 85% water, which helps the bird maintain fluid balance in drier habitats.
Kiwi routinely consume a wide array of insect larvae, including grubs from beetles and craneflies. Other common prey includes adult beetles, spiders, millipedes, and centipedes residing in the soil or leaf litter. This energy-rich invertebrate diet is closely linked to the bird’s reproductive success, as they must build substantial reserves for the breeding season.
Supplemental Plant and Fungal Items
Kiwi are omnivores that opportunistically consume plant-based foods to supplement their invertebrate diet. They forage for fallen fruit and berries from native New Zealand plants, which provide seasonal carbohydrates and sugars. Specific plant matter consumed includes the leaves and fruits of species like Coprosma, Hinau, Miro, and Tōtara.
The Hinau fruit is an important energy source for certain kiwi populations when available. Brown kiwi also consume bracket fungi, seeds, and general leaf litter. These items contribute to a balanced, varied diet across different habitats.
Specialized Foraging Behavior
The kiwi’s method of finding food is distinct, relying on sensory adaptations suited for its nocturnal environment. It possesses a highly developed sense of smell, unusual for avian species, supported by a large olfactory bulb in its brain. This sense is maximized because its nostrils are located at the very tip of its long, slender bill.
The kiwi uses its bill for a specialized technique called “probing,” plunging the beak up to 12 centimeters deep into the soil to locate prey. As it walks, the bird frequently taps the ground, making characteristic snuffling sounds as it draws air through its sensitive nostrils. The bill tip also contains sensory pits equipped with mechanoreceptors. These allow the kiwi to detect the minute vibrations of invertebrates moving beneath the surface, enabling effective hunting of subterranean prey in the dark.