Appendix G. Territory location within patch and constraints on natal dispersal distances.
With regard to our test of the natal dispersal model of sex ratio adjustment (Julliard 2000), it is important to note that constraints on natal dispersal will slightly differ for offspring depending on the location of their natal territory within the patch (on the edge vs. in the center - see figure below). The probability of settling in the natal patch may differ between offspring from pairs breeding in the centre and on the edge of patches. Offspring from territories in the centre of patches would have to disperse distances larger than 575 m on average to change patch, while offspring from territories at the edge of patches would have to disperse only 350 m . However, the boxes available within a radius of 500 m are in both cases located in majority within the natal patch: 100% and 75% of boxes for offspring hatched in central and edge territories respectively. Furthermore, the large between-patch areas, which contain no nest boxes, should enhance the difference between males and females in the probability to settle in the natal patch. Dispersal distance distributions were recorded under a continuous distribution of nest boxes. When facing large zones with no available breeding sites, we expect that males would be more prone to stay in their natal patch while females would be more prone to leave.
|FIG. G1. Location of the different types of territories within a patch. White squares: nest boxes in edge territories; gray squares: nest boxes in central territories. The mean number of territories located on the edge of a patch is 17.9 ± 0.19 (each patch comprising 30 territories).|