https://www.redkites.net/section72403_17698.html
THE NEST. The nest is built high up in a tree usually on the edge of woodland, which enables a smooth flightpath into the nest for the large winged parents. A large number of nests are built in beech trees in the Chilterns. The nest consists of twigs and a neat 'bowl' usually lined with sheep wool or other material. Kites are known to 'decorate' their nests with items such as lottery tickets, teddy bears, plastic bags, gloves, etc.
When I had a rook's nest removed from low down in my chimney last year the sweep said he regularly found yorkshire puddings in their nests and once even a car number plate!