Blue tit nest part 3

In the header photograph, the blue tit’s eggs are lying in a cup shaped nest lined with soft feathers that are obviously intended to keep the eggs warm. But around the edge of the cup there are larger feathers; their purpose is not so clear.

For a start, observational studies have shown that it is the male blue tit that brings these large feathers to the nest, and he always places them on the edge of the cup, his only contribution to the whole process of nest building. The studies have found that males that carry feathers to ornament their nest this way are fathers to larger clutches of eggs and feed their nestlings more often. More of those nestlings fledge, in better body condition, than the those from a nest that has not been ornamented with showy feathers.

Blue tit nest with and without large feathers around the edge of the cup.

Finally, male blue tits that ornament their nests have bigger feet and their mates survive the processes of egg-laying and chick-rearing in better than average body condition. It seems that carrying large feathers to ornament a nest is, somehow, an indicator that the male will be a good parent.