Temporal variation in flock size and habitat use of parrots in New Caledonia

Abstract

We examined daily activity patterns, flock-size variations, use of vertical space, and small-scale habitat selection of the New Caledonian Parakeet (Cyanoramphus saisseti), horned Parakeet (Eunymphicus cornutus), and New Caledonian Rainbow lorikeet (Trichoglossus haematodus deplanchii) on mainland New Caledonia. All three species had bimodal patterns of activity, with most encounters occurring in the morning and a second smaller peak of encounters in the late afternoon. The parakeets were usually seen singly or in twos, and most flocks contained fewer than four individuals. Parakeet flocks remained relatively consistent in size through the day and through the year. Most Rainbow lorikeet flocks contained only a few individuals, though some reached up to 40 birds. Rainbow lorikeets were encountered mainly in small flocks during the breeding season from September to January, and their average flock size was higher and more variable for the rest of the year. Rainbow lorikeets selected valley forest and urban areas, where they were most common in parks and gardens. New Caledonian Parakeets favored slope forest over valley forest, and they foraged low, either at the edge of forest, in slope forest, or in maquis (shrubland). horned Parakeets generally fed at greater heights than did New Caledonian Parakeets, preferred valley forest to slope forest, and avoided maquis. we suggest that the observed difference in habitat use between the New Caledonian Parakeet and horned Parakeet is the result of spatial resource partitioning, which allows these closely related species to coexist. © The Cooper Ornithological Society 2012.