Journal ArticleDOI
Estimation of parrot and hornbill densities using a point count distance sampling method
TLDR
In this paper, the suitability of point count distance methods for estimating densities of tropical parrots and hornbills was assessed during surveys in Indonesia, and the authors concluded that point counts are likely to be less biased than line transects because bird detection rates close to the recorder may be higher and there may be less chance of double counting.Abstract:
The suitability of point count distance methods for estimating densities of tropical parrots and hornbills was assessed during surveys in Indonesia. The methods will perform well, so long as the following are considered. (1) Enough bird records must be accumulated to model species' detection curves precisely. For some species, around 2000 point counts may be needed and, in very rare species, the method may not be appropriate. Pooling data across habitats, species or years may increase precision in cases of small sample size. (2) Point counts are likely to be less biased than line transects because bird detection rates close to the recorder may be higher and there may be less chance of double-counting birds. Distances greater than 400 m between census points are unnecessary. (3) Count periods lasting ten minutes may be needed to ensure that most birds close to the recorder are detected. Controlled flushing of concealed birds after the main count period may also be appropriate. (4) The best time of day for census is the period when bird detectability is high but bird mobility low. For many large avian frugivores, this corresponds to the period between one hour after dawn and 10.30 h. (5) Records of flying birds must be excluded from density calculations. In the species studied, between 2% and 20% should be added to density estimates to compensate for the exclusion of flying birds.read more
Citations
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Journal ArticleDOI
Estimating bird abundance : making methods work
TL;DR: This work considers strategies to ease the implementation of distance sampling methods, to enhance their reliability, to adapt the methods for difficult species, and to deal with circumstances in which representative sampling is problematic.
Journal ArticleDOI
Bird diversity and abundance in forest fragments and Eucalyptus plantations around an Atlantic forest reserve, Brazil
TL;DR: Bird species richness at points in forest fragments did not decline with fragment size, distance from the reserve, or forest quality, however, forest in fragments was more heavily degraded than forest within the reserve and poor forest quality may be the cause of declines in some species.
Journal ArticleDOI
Factors influencing the abundance of parrots and hornbills in pristine and disturbed forests on New Britain, PNG
TL;DR: Current abundance of such bird species may be a poor correlate of future extinction risk as long-lived taxa may remain common for some period even when annual recruitment has declined to critically low levels.
Journal ArticleDOI
Adjusting count period strategies to improve the accuracy of forest bird abundance estimates from point transect distance sampling surveys
David C. Lee,Stuart J. Marsden +1 more
TL;DR: It is suggested that movement away from the recorder is more common than attraction to the recorder, and that unless pilot studies show otherwise, similar studies should not use a settling down period for surveying many species.
Journal ArticleDOI
Flowers, fruits, and the abundance of the yellow-chevroned parakeet (Brotogeris chiriri) at a gallery forest in the South Pantanal (Brazil)
TL;DR: Evaluated flower and fruit production at a gallery forest in the Pantanal flood plain (Brazil) in order to evaluate the relationship between food resource production and abundance of a common parakeet, Brotogeris chiriri, and found no evidence for gallery forest use for roosting and/or breeding.
References
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Journal ArticleDOI
A Variable Circular-Plot Method for Estimating Bird Numbers
TL;DR: In this article, a variable strip transect count is used to estimate the number of birds seen or heard around a station, and estimates the horizontal distance from the station to each bird.
Book ChapterDOI
Assessment of Counting Techniques
TL;DR: In this paper, the suitability of various counting methods for various purposes in a variety of field studies of birds are discussed. But this is not a thorough review of the topic.
Journal Article
Forest Bird Communities of the Hawaiian Islands: Their Dynamics, Ecology, and Conservation
Journal ArticleDOI
The effect of selective logging on the primate populations in the Budongo Forest Reserve, Uganda
TL;DR: It is concluded that Cercopithecus mitis and C. guereza have benefited from logging in Budongo and that logging has had little effect on the other two primates.