Definition: A taxon is Endangered when the best available evidence indicates that it meets any of the
criteria A to E for Endangered, and it is therefore considered to be facing a very high risk of extinction in the wild.
Definition: A depression caused by erosion by water or ice. Low-lying land bordered by higher ground; especially elongate, relatively large gently sloping depressions of the Earth's surface, commonly situated between two mountains or between ranges of hills or mountains, and often containing a stream with an outlet.
Definition: Type of food comprising the majority
of the diet of an animal.
Attribution: Richard M. Sibly, Christopher C. Witt, Natalie A. Wright, Chris Venditti, Walter Jetz, and James H. Brown. 2012. Energetics, lifestyle, and reproduction in birds. PNAS 109(27):10937-10941, doi:10.1073/pnas.1206512109