THE GIANT HUMMINGBIRD PATAGONA GIGAS IN ECUADOR

The Giant Hummingbird Patagona gigas was studied in highland Ecuador in 1968–70. The northern and southern limits of its known distribution were extended, but east-west range and altitudinal limits were as restricted as noted by other authors. Its distribution elsewhere in South America is also reviewed, as are the taxonomy of various populations and breeding records. It is concluded that northern Ecuador is not reached by migrants from central Chile.
Locally, Agave americana was the principal source of nectar, and the Ecuadorian range of the bird corresponds with the distribution of this plant. Further south, where the birds occur over a wider range of elevations, other plants are visited. It is suggested that the availability of nectar and the presence of competitors in combination determine the distribution of the Giant Hummingbird. The Ecuadorian population is probably prevented from northward extension by conditions unsuitable for Agave americana . There is evidence that this plant is exotic to Ecuador; its introduction may have permitted the Giant Hummingbird to expand its range from Peru.