From the project page: 

The Growth That Is Our Own Cradle enquires into the form and make up of a selection of British bird’s nests. Nine nests from different species of birds are carefully studied and documented in order to heighten our appreciation of each construction.

They are so delicate in design. A nest might have a thousand pieces to its make up. Each piece taken on a single trip. Not only that but the birds have to find each piece, and find a place for it in their nest. It’s like a builder building a house. Their construction: unbelievable that they never fall out and are so safe. Built for strength but also for comfort. Amazing really, that birds can make these homes like they do.

(Fred Mills, nest finder)