White-tailed goldenthroat

The white-tailed goldenthroat ("Polytmus guainumbi") is a species of hummingbird in the family Trochilidae.
It is found in Argentina, Bolivia, Brazil, Colombia, French Guiana, Guyana, Paraguay, Peru, Suriname, Trinidad and Tobago, and Venezuela. Large populations can be noted east of the Andes, from the Amazons to San Juan, and from east Columbia to northern Brazil, just north of the Amazon.
Its natural habitats are dry savanna and subtropical or tropical seasonally wet or flooded lowland grassland.
The white tailed goldenthroat carries an affinity for water, unlike its smaller counterpart, the Green Tailed goldenthroat for which its often mistaken. 
Their similar appearances and behavior, such as trap-lining nectar resources and spending a lot of time hawking and gleaming tiny insects, make them easy to mistake for one another. 
References.
2. Hilty, S. (2003). Hummingbirds. In Birds of Venezuela (p. 415). Princeton, New Jersey: Princeton University Press.