Sex‐biased dispersal is often connected to the mating behaviour of the species. Even if patterns of natal dispersal are reasonably well documented for monogamous birds, only a few data are available for polygynous and especially lekking species. We investigated the dispersal of the capercaillie (Tetrao urogallus) by examining sex‐specific gene flow among the leks. Genetic information was extracted using nuclear and mitochondrial molecular markers for sexed faecal samples and analysed by novel Bayesian statistical methods. Contrary to the traditional view that the males are highly philopatric and female is the dispersing sex, we found roughly equivalent gross and effective dispersal of the sexes. The level of polygamy has a strong influence on the effective population size and on the effective dispersal. The results do not support the theories that dispersal evolves solely as a result of resource competition or other advantages to males obtained through kin selection in lekking species.

SUMMARYA variational principle and the corresponding finite element equations for determination of the stream function for soil seepage problems is given using the standard finite element potential solution as data. The procedure is very simple and independent of the element type employed. Generalization of the method to multiply connected domains is included.

SUMMARYA procedure to generalize Kirchhoff thin plate finite elements so that they can be used for solving thick Mindlin plates is presented. Two typical discrete Kirchhoff elements, a triangular one and a quadrilateral one, are modified. Numerical results for a clamped circular plate show that the accuracy of the new Mindlin elements is the same as that of the original Kirchhoff elements and they can be used in the whole thickness range of Mindlin plate theory.

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