Our objective was to address the hypothesis that satellites and independents are genetically distinct , possessing one of two alleles at a single genetic locus. Dr. Dov Lank has constructed a multigenerational pedigree and used it to address the hypothesis that the satellite trait is an autosomal dominant gene. If the trait is autosomal, then female ruffs should also have the gene, even if they do not express it. We tested the genetic hypothesis by implanting post-breeding females with testosterone, causing them to temporarily exhibit male breeding behaviour. We found that female ruffs exhibited display behaviour that followed their parentage.
Most ducks form pair bonds during the winter, long before they reproduce.
Winter pair-bond formation is a puzzling phenomenon. There is large interspecific variation in pairing date, and a number of hypotheses attempt to explain this variation. Most concentrate on the energetic benefit that paired females derive from associating with dominant males. Two of these make the prediction that larger species of waterfowl should form pair bonds earliest. Our ability to test these hypotheses is hindered by our lack of knowledge of the pairing chronologies of many duck species, particularly sea ducks.