Monday, July 6, 2020

Changes in bird conspicuousness at Pureora Forest

TitleChanges in bird conspicuousness at Pureora Forest
Publication TypeJournal Article
Year of Publication2004
AuthorsSmith, ANH, Westbrooke, IM
Type of Articlepaper
Keywordsbird fauna, bird populations, conspicuousness, five-minute bird counts, New Zealand, Pureora Forest

Five-minute bird counts in Pureora Forest Park were compared between one site in a 1978-81 study and two similar sites in a 1997-98 study. The two sites from the more recent study have had different levels of pest control since the historical survey. The mean number of birds detected per count was calculated for each species and the differences among the sites were tested for significance. The results suggest a dramatic decline over time (irrespective of pest control) in many small native insectivores, including the grey warbler (Gerygone igata), tomtit (Petroica macrocephala ), fantail (Rhipidura fuliginosa) and rifleman (Acanthisitta chloris). A large increase in bellbird (Anthornis melanura) conspicuousness was detected. Increases were observed for robin (Petroica australis), kokako (Callaeas cinerea wilsoni), kaka (Nestor meridionalis), parakeet (Cyanoramphus novaezelandiae) and kereru (NZ pigeon Hemiphaga novaeseelandiae) between the historical site and the recent pest-controlled site, but tui (Prosthemadera novaeseelandiae) counts have decreased. The number of species with higher mean counts in the site with more intensive pest treatment suggests that pest control has had a positive effect on some bird populations. However, some species also increased at the site with less-intensive treatment, and tui is more conspicuous at this site than the controlled one. The study shows the value of historical bird count surveys for assessing long-term changes in bird populations, and suggests a need to make similar data sets from around New Zealand more readily available to researchers.

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