Nesting instincts

Spring is the busiest time of year for the birds in my garden. In my nestbox, a female blue tit has just taken up residence. She has been building her nest by collecting moss and grass, and piling it into the box until it is about half full. She has left a space in the corner, away from the entrance hole, where she will construct the nest cup. Soon, she will switch to collecting hair and feathers to heap on top of the moss – then she will lay her first, delicately speckled, white egg, which she will hide in the feather-filled hole. Only when her clutch of 10 eggs is nearly complete will she fashion the hair and feathers into a neat little cup within the space in the moss layer, and start the process of incubation.

Structure is as varied as location. The finch family in particular illustrates just how diverse nests can be.

Over in the ivy, a female blackbird has already finished building