Kiwis are strictly monogamous, usually pairing for at least two to three breeding seasons, sometimes for life (2). These birds are extremely territorial and, once mating pairs form, the nesting region is fiercely defended, usually by vocal displays but occasionally by physical battles (2) (4). Males are particularly aggressive towards intruders and are capable of inflicting fatal wounds with their powerful feet and legs, but serious injuries and death are rare and territories seldom change ‘ownership’ unless the resident male dies naturally or is crippled. Within these territories kiwis may have up to 100 different excavated burrows and usually use a different one each day for shelter (2). However, unlike other kiwi species, the great spotted kiwi prefers dens to simple burrows, constructing tunnels several metres long and with more than one exit (4).
Most breeding takes place in spring. The great spotted kiwi only produces one enormous egg per clutch, reaching up to 15% of the female’s body mass (4). The egg takes up so much space that the females cannot generally eat during the last few days before laying, so must accumulate a store of fat beforehand (2). The advantage is that this large, nutrient-rich egg produces fully-feathered young at an advanced stage of development, quickly able to take care of themselves (2) (5). The egg is incubated by both parents (4) for about 70 days, and within ten days of hatching the chick begins to hunt for food unaccompanied outside the nest, but returns to the nest each day for three to four weeks (5). The chick may feed during the day for the first six weeks of life, but then becomes exclusively nocturnal.
Kiwis set out on their hunt for food about 30 minutes after sunset, in search of insects, snails, spiders, earthworms, crayfish, fallen fruits and berries on which to feed (2) (5). Prey is found by the birds tapping the ground with their beaks and sniffing the earth, followed by plunging their beaks deep into the soil, stabbing back and forth to catch underground quarry (2).