Physical Condition of an Animal, Using as an Example the Common Eider, Somateria mollissima

Arnaud J. Cabanac


An index of the physical condition of an animal should describe its endogenous available energy. The welfare of the animal depends on its ability to spend its stored energy (lipid and protein) in order to survive the environmental and behavioural challenge at the particular time of its capture. I propose a new index to predict the survival chance of the subject. The new index of physical condition takes into account the available endogenous energy reserves and the known needs of the species at that particular time of year. I further illustrate this new method of estimating the physical condition by running a trial with Common Eiders, Somateria mollissima.


Behaviour; ecology; physiology; management; fitness

Full Text:



Volumes that are more than six years old are freely available courtesy of the Biodiversity Heritage Library.


Questions or problems with the website? Contact William Halliday (info -at- canadianfieldnaturalist -dot- ca).