Plant-Species Preferences of Birds in Lowland Rimu (Dacrydium cupressinum) Forest—Implications for Selective-Logging

Plant species preferences of birds were determined by comparing the proportional bird use of plant species during direct observations with the proportions of plant species present on point-height intercepts in lowland rimu (Dacrydium cupressinum) forest in North Okarito, Westland. Plant species and bird use of plant species were divided into 5 m height classes, and rimu trees were divided into four age classes (sapling, pole, mature, and old). The frugivorous New Zealand pigeon (Hemiphaga novaeseelandiae) used mature and old rimu more than expected from the proportion of these age classes present, and it preferred the upper tiers of the forest. The omnivorous tui (Prosthemadera novaeseelandiae) had similar preferences to the pigeon. Other omnivorous species, viz., the bellbird (Anthornis melanura) and silvereye (Zosterops lateralis), shared preferences with both the pigeon and insectivorous species. Most insectivorous species, viz., the brown creeper (Mohoua novaeseelandiae), grey warbler (Gerygone igata), New Zealand fantail (Rhipidura fuliginosa), New Zealand tomtit (Petroica macrocephala), and rifleman (Acanthisitta chloris), used pole rimu more than expected and preferred the middle and lowest tiers. The insectivorous New Zealand robin (Petroica australis) had no preference for any plant species but had a strong preference for deadwood and the lowest tier of the forest. Of the 10 species sufficiently abundant to be monitored, the pigeon, bellbird, and tui are most likely to be detrimentally affected by selective-logging of mature and old rimu.