Feeding ecology of hybridizing parakeets on Mangere Island, Chatham Islands
|Title||Feeding ecology of hybridizing parakeets on Mangere Island, Chatham Islands|
|Publication Type||Journal Article|
|Year of Publication||1994|
|Type of Article||paper|
The diet of Red-crowned Parakeets (Cyanoramphus novaezelandiae chathamensis) and hybrids (C. n. chathamensis x C. auriceps forbesi) was determined from crop contents and field observations. Crops were dissected from 220 Red-crowned and hybrid birds collected over four years on deforested Mangere Island in the Chatham group. Volume and prevalence of foods taken in winter, spring and summer were measured. No effect of sex or age was found on frequency of occurrence of food items, and low variation in diet attributable to species hybrid status indicated that feeding strategies of the parent species had converged. Diet of all forms varied seasonally. The main winter food was grass seeds, with a small proportion of leaves. The spring diet was the most varied, consisting mostly of leaves, with seeds, flowers and invertebrates. Seeds were eaten in late summer, mostly from Geranium traversii. Field observations in winter emphasised the importance of leaf feeding. Some plant species seen to be eaten in summer were not found in crops. Habitat selection and perch height distribution was associated with breeding requirements as well as feeding.