An intriguing association....
Sometimes, relationships between swans are not as they seem and recent observations have certainly left us wondering about three particular Slimbridge visitors. For the past six years, a swan named Nero has spent her winters at the reserve with what we assumed to be her mate, Illya. Courtship dances were observed and they were rarely far from each others sides, although they never brought cygnets back with them.
Last winter, we noticed that Illya and Nero were accompanied by another adult named Illyan, and all three spent the winter here as a ménage à trois! Unusually, there seemed to be no acts of aggression towards imposter Illyan who was accepted very readily. The tale took another strange twist this week, when Nero flew in with Illyan. Despite searches, Illya is no where to be seen!
So what is occuring here? Perhaps the three birds are related in some way. Are Illyan and Nero siblings or step-siblings? Or was Illya the father of Nero rather than her mate? Bewick's swans have been known to associate with their parents for up to seven years after birth, although this is very unusual, with most gaining independence after two years. If these birds are unrelated, could this be another case of divorce? We have seen only two cases of divorce during 45 years of studying the swans at Slimbridge. As only Illya was ringed and the parentage of each swan is not known, we cannot be certain that they are related and will therefore never fully unravel this intriguing puzzle....
