Answer the following question: Information:  - Birds (Aves), also known as avian dinosaurs, are a group of endothermic vertebrates, characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a lightweight but strong skeleton. Birds live worldwide and range in size from the bee hummingbird to the ostrich. They rank as the class of tetrapods with the most living species, at approximately ten thousand, with more than half of these being passerines, sometimes known as perching birds or, less accurately, as songbirds.  - Hummingbirds are birds from the Americas that constitute the family Trochilidae. They are among the smallest of birds, most species measuring . Indeed, the smallest extant bird species is a hummingbird, the 5-cm bee hummingbird weighing less than a U.S. penny (2.5 g).  - Mitrospingus is a genus of bird formerly in the family Thraupidae . Established by Robert Ridgway in 1898 , it contains the following species : Dusky - faced tanager ( Mitrospingus cassinii ) Olive - backed tanager ( Mitrospingus oleagineus ) The name Mitrospingus is a combination of the Greek words mitra meaning `` cap '' or `` head - dress '' and spingos , meaning `` finch '' .  - The ostrich or common ostrich ("Struthio camelus") is either one or two species of large flightless birds native to Africa, the only living member(s) of the genus "Struthio", which is in the ratite family. In 2014, the Somali ostrich ("Struthio molybdophanes") was recognized as a distinct species.    Given the information, choose the subject and object entities that have the relation of 'continent'.
Answer:
mitrospingus , the americas