Damage to 6 orchards of apples, pears, plums and nectarines in Western Australia by the parrots Purpureicephalus spurius, Platycercus icterotis and Barnardius zonarius was studied in 1973-75 and damage by the cockatoo Calyptorhynchus funereus baudinii was recorded opportunistically for comparison. There was up to 12% damage to individual varieties of fruit, least to green varieties of apple. In any one season no single orchard had losses over 1.4% of total fruit grown and none had net income affected by more than $A100. Damage by those smaller parrots was of little economic significance during the study. The cockatoo caused more damage to apples, and in a shorter time, than did the small parrots.
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J.L. Long (1985) studied this question.
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