The Gilded Sapphire or HummingbirdHylocharis chrysura, in the Trochilidae family. It is found in a wide range of open and semi-open habitats in southern Brazil, Bolivia, Paraguay, Uruguay and northern Argentina. It is overall greenish-golden with a coppery tail, whitish-buff underparts, a rufus chin, and a slightly decurved, black-tipped red bill.
This bird was photographed at Reserva Natural Otamendi, Argentina