Published by the Foundation for Open Access Statistics Editors-in-chief: Bettina Grün, Torsten Hothorn, Edzer Pebesma, Achim Zeileis    ISSN 1548-7660; CODEN JSSOBK
Authors: Birgit Erni, Bo T. Bonnevie, Hans-Dieter Oschadleus, Res Altwegg, Les G. Underhill
Title: moult: An R Package to Analyze Moult in Birds
Abstract: Moult is the process by which birds replace their feathers. It is a costly process in terms of energy and reduced flight ability but necessary for the maintenance of the plumage and its functions. Because birds generally avoid to moult while engaged with other energy demanding activities such as breeding and migration, the analysis of moult data gives insight into how birds fit this life stage into the annual cycle, on time constraints in the annual cycle, and on the effects of environmental variables on the timing of moult. The analysis of moult data requires non-standard statistical techniques. More than 20~years ago Underhill and Zucchini developed a likelihood approach for estimating duration, mean start date and variation in start date of a population of moulting birds. However, use of these models has been limited, mainly due to the lack of user-friendly software. The moult package for R implements the Underhill-Zucchini models, allowing the user to specify moult models in a regression type formula. In addition the functions allow the moult parameters (duration, and mean and variation in start date) to depend on explanatory variables. We here describe the package, give a brief summary of the theory and illustrate the models on two datasets included in the package.

Page views:: 2649. Submitted: 2011-05-20. Published: 2013-02-07.
Paper: moult: An R Package to Analyze Moult in Birds     Download PDF (Downloads: 2449)
Supplements:
moult_1.2.tar.gz: R source package Download (Downloads: 453; 28KB)
v52i08.R: R example code from the paper Download (Downloads: 530; 6KB)

DOI: 10.18637/jss.v052.i08

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Paper: Creative Commons Attribution 3.0 Unported License
Code: GNU General Public License (at least one of version 2 or version 3) or a GPL-compatible license.