Endangered birds are species of birds that are at risk of becoming extinct due to human activities, climate change, and other environmental factors. The three endangered birds mentioned in the crossword solutions are the CRANE, whooper, and peregrine falcon. The CRANE is a large bird with long legs, a long neck, and a long bill. The whooper is a large swan-like bird with a yellow bill and black legs. The peregrine falcon is a large bird of prey with a dark back and a white chest. All three of these birds are considered endangered and are at risk of becoming extinct.