PLUMAGE QUALITY AND MATE CHOICE IN MALLARDS (ANAS-PLATYRHYNCHOS)

The suspected relevance of plumage quality of drakes for the choice of mates by ducks has been confirmed in a series of experiments. Drakes were ranked according to the extent of naturally occurring blemishes (deviations from the plumage of an ideal drake) and introduced, two at a time, to a resident group of female “adjudicators”, who would choose drakes by following one of them and/or by performing aggressive acts against one or both. We could predict the outcome in almost every case. In other experiments we could influence female choice by making attractive drakes ugly or unattractive ones more beautiful by means of staining and bleaching. The success in these experiments of isolating the effects of plumage quality from the many other factors which usually influ- ence mate choice in females was a consequence of the drakes’ apparent lack of interest in the females to whose pen they were introduced for a short time only. When several females chose the same good looking male, intense rivalry and aggressive behaviour occurred among the females. The possible effect of such rivalry on female mate choice was briefly examined; it appeared to be unimportant in our experiments. © 1990, Brill. All rights reserved.