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 Nest (aviary) Chiapas and Yucatán. Birds from other continents include are toucans, herons, flamingos, peacocks, and macaws. The Nest (aviary) The Nest () is an aviary located in Ixtapaluca, state of Mexico. Founded by veterinarian Jesús López Estudillo in the 1960s, it is a civil association created to preserve over 300 different species of birds, both Mexican and the rest of South America, Africa and Asia, mostly endangered. The association—formerly known as " Wildlife " ()—also has a space for breeding and conservation of the most endangered species. The Nest is the most diverse aviary in the world and the third largest