Bird nest July to September), it is not in others, and the swiftlets are declining in areas where the harvest reaches unsustainable levels. Some species of birds are also considered nuisances when they nest in the proximity of human habitations. Feral pigeons are often unwelcome and sometimes also considered as a health risk. The Beijing National Stadium, principal venue of the 2008 Summer Olympics, has been nicknamed "The Bird Nest" because of its architectural design, which its designers likened to a bird's woven nest. In the Victorian era, naturalists often collected bird's eggs and their nests. The study of bird nests is
The Life of Birds prospective companion on its nest-building ability, and this is a conspicuous part of the weaver's behaviour. The bowerbird puts on one of the most elaborate displays: a hut-like construction, completed by a collection of objects designed to impress. Competition among males can be fierce and in Scotland, Attenborough observes rival capercaillies engaging in battle — after one of them chases the presenter. Avian polyandry is not widespread, but is illustrated by the superb fairy-wren, where the male's family can easily comprise young that it did not father. Broadcast 9 December 1998, this episode explores the lengths to which birds will