Foraging ecology of the red-crowned parakeet (Cyanoramphus novaezelandiae novaezelandiae) and yellow-crowned parakeet (C. auriceps auriceps) on Little Barrier Island, Hauraki Gulf, New Zealand

The diet of red-crowned parakeets (Cyanoramphus novaezelandiae novaezelandiae) and yellow-crowned parakeets (C. auriceps auriceps) was compared on Little Barrier Island, New Zealand between 1986 and 1987. Significant dietary differences were observed in these sympatric, congeneric species. Yellow-crowned parakeets ate significantly more invertebrates than red-crowned parakeets, which fed on a greater variety of plant foods. Red- crowned parakeets were found in all vegetation types depending on the availability of food and were commonly seen foraging on the ground in open habitats. In contrast, yellow-crowned parakeets were more arboreal and showed distinct preferences for forested habitats. The existence of both parakeet species in sympatry is examined as is the ecological importance of invertebrate food sources. Observed differences in the behaviour and ecology of parakeet species on Little Barrier Island are used to provide insight into the present day distribution and status of parakeets on mainland New Zealand.