The courtship ritual of the dunnock (Prunella modularis) is peculiar. I observed a pair on the lawn in our garden last week while I was sitting at the garden table working at my laptop. The female had raised her tail feathers and was fluttering them up and down rapidly while the male pecked repeatedly at her rear end, well her cloaca to be more specific. It went on for a minute or two until they both flew up quickly into a hedge, presumably to mate.
It’s not a ritual I’d observed before and Googled the bird to discover that female dunnocks are quite promiscuous. The pecking of the cloaca by the male is thought to stimulate rejection of sperm from a previous male’s mating and so increase the chances of the new mate fathering her offspring. However, in my garden observations I could have sworn I could see something curved and white protruding from the female, an egg, perhaps. So maybe the male’s pecking stimulates her to lay an egg outside the nest before he takes her back to mate. Either way, it’s apparently not an entirely efficient paternity-assurance strategy as genetic testing of dunnock broods has revealed that the female can lay eggs fertilised by several males.
I only had my phone to hand so this is awful footage and the voyeuristic blackbird is a distraction.