The beak of the kakapo is adapted for grinding food finely . For this reason , the kakapo have a very small gizzard compared to other birds of their size . It is generally herbivorous , eating native plants , seeds , fruits , pollen and even the sapwood of trees . A study in 1984 identified 25 plant species as kakapo food . It is particularly fond of the fruit of the rimu tree , and will feed on it exclusively during seasons when it is abundant . The kakapo have a distinctive habit of grabbing a leaf or frond with a foot and stripping the nutritious parts of the plant out with its beak , leaving a ball of indigestible fibre . These little clumps of plant fibres are a distinctive sign of the presence of the bird . The kakapo is believed to employ bacteria in the fore @-@ gut to ferment and help digest plant matter .