Behavioural Dimorphism in Male Ruffs, Philomachus Pugnax (L.)

• Published in: Behaviour
• Main Author: Van Rhijn, J.G.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Brill 1973
• Subjects: Philomachus pugnax; Ruff
• Online Access: http://dx.doi.org/10.1163/156853973x00076; https://brill.com/view/journals/beh/47/3-4/article-p153_1.xml; https://brill.com/downloadpdf/journals/beh/47/3-4/article-p153_1.xml

Abstract In the Ruff two groups of males can be distinguished: independent males and satellite males. This classification is based upon differences in territoriality and behaviour, and is highly correlated with differences in the nuptial plumage. Independent males are mostly dark coloured; their behaviour contains much fighting and related activities. They can be subdivided into resident males and marginal males. Resident males defend territories (residences), marginal males do not. Satellite males are mostly white. They behave peacefully and do not defend a territory. Satellite males have access to the residences on an arena (cfr. HOGAN-WARBURG, 1966). In this study an attempt has been made to throw some more light upon the behavioural dimorphism (independent males versus satellites). On the one hand I tried to analyse the causation of this phenomenon, on the other hand I was interested in its biological significance. I have tackled these problems by means of an examination of film material, and by a quantitative study of the behaviour on different arenas (leks) in the field. The film supplied me with detailed data about the behaviour of resident males, satellite males, and females in different external situations. On the basis of these data it was possible to analyse the temporal associations between the various behavioural units, for this purpose divided into "postures", "locomotion sequences", "action sequences", and "actions". The observed relations were largely similar for the three categories of individuals. For this reason I was able to compose one model for the hypothetical causal mechanism underlying the behaviour of resident males, satellite males, and females. The display of postures was supposed to be controlled by the values of two variables, the display of the other units by the value of the same variables and directly by the external situation. The values of both variables depended on external stimuli and on the internal situation (partly determined by previous external stimulation) I could not ...