One of the smallest birds-the purple throated carib must work very hard to cultivate and defend his territory. Successful male caribs maintained and defended the nectar 
supplies in his territory. These supplies were two to five times greater than their daily needs plus part of its nectar crop must contain a stock of heliconia flowers for visiting female to dine on.
Male and female purple throated caribs are alike in plumage, but males are considerably larger and have longer wings than females. Females, however, have bills that are 20 percent longer and 30 percent more curved than the bills of the males, allowing them to feed from flowers that males cannot. Seems that male and female energy needs match the energy derived from the flowers they sip.
Male caribs feed from the Caribbean heliconia
(Heliconia caribaea)(image left),
while females feed primarily from the lobster claw heliconia
(Heliconia bihai)(image at the right).
Heliconia b. used by female carib
Purple-throated Carib [Eulampis jugularis] plumage is largely black. Its throat is purplish red with its tail and upper tail feathers colored bluish green. Wings are a metalic green. The Purple-throated carib is a hummingbird species native to the mountainous islands of the Eastern Caribbean where John Kress and Ethan Temeles, an ornithologist and biology professor at Amherst College in Massachusetts, have spent several years researching purple throated caribs in the wild on the island of Dominica.
Resources
Excerpts courtesy of http://bit.ly/a4hAPW
Image 1. courtesy of http://bit.ly/bthiW2
Image 2. courtesy of http://bit.ly/bbO25F
Image 3. courtesy of http://bit.ly/aA1FMD
