Great crested Grebe (Podiceps cristatus), Marsworth reservoir, Hertfordshire, 14/04/2013. Two days after I watched the pair performing the courtship displays, the pair are now attending to a nest site. I watched them building the nest together yesterday. At various points, after a reed stem had been carefully gathered and laid across the structure, the female would lie prostrate across the nest whilst the male lingered around her rear end. Knowing that mating takes place on the nest, I have no doubt the male eventually did climb on and mate with the female. I don't think the bird is on eggs yet but let's hope the Grebes don't get flooded out this year.