Abstract:

Considerations on the migrations of two neotropical hummingbirds. Giant Hurnmingbirds,are seasonally common in central Chile and adjacent Argentina where they nest, but they are not seen there from mid autumn to mid winter, and very few museum specimens from this distinct population are available from areas elsewhere so that only weak inferences can be made about the location of their wintering grounds. Fire Crowns are numerous in central Chile from autumn to winter but there is a marked decline in density from early spring to late summer. The destination of these hummingbirds was unknown for a long time but now it is known that the species moves to the south of Chile and Argentina for breeding. The only other species in the genus, S. fernandensis is divided into two subspecies. This is in sharp contrast with the lack of subspecific differentiation of the Más a Tierra population of S. galeritus, and warrants further investigation.