Elaenias are rather cryptic small flycatchers of the American tropics. This species is highly migratory and there is a vagrant record from southern Texas. Six subspecies are divided into three groups. This is a member of the "Chilean" group characterized by a long primary projection (p10 usually longer than p5) combined with strongly white wing-bars and crown patch. Genetic studies have shown this species to be polyphyletic and it seems likely that at least three species deserve recognition. One genetic study found the race E. a. chilensis to be closer to the Sierran Elaenia (E. pallatangae) than to other races of White-crested Elaenia.
Reference
Schulenberg, Thomas S.. 2009. White-crested Elaenia (Elaenia albiceps), Neotropical Birds Online (T. S. Schulenberg, Editor). Ithaca: Cornell Lab of Ornithology; retrieved from Neotropical Birds Online: http://neotropical.birds.cornell.edu/portal/species/overview?p_p_spp=30734
Nikon P510 Point-and-shoot.