FIRST REPORT OF NECTAR ROBBING BY SWORD-BILLED HUMMINGBIRDS ENSIFERA ENSIFERA

Abstract

A growing number of hummingbird species are known to practice nectar robbing. Hummingbirds that rob nectar tend to have short bills and to rob flowers with long, tubular corollas that prevent the birds from accessing nectar through its openings. We document that Sword-billed Hummingbirds Ensifera ensifera, which have the longest bills of any hummingbird species, are secondary nectar robbers on flowers of the red angel’s trumpet Brugmansia sanguinea, which have long tubular corollas and are regularly pollinated by Sword-billed Hummingbirds. When obtaining nectar through the floral opening of B. sanguinea, Sword-billed Hummingbirds' heads may be completely enveloped by the flower, severely limiting their vision. Sword-billed Hummingbirds might be at a lower risk of predation when they rob nectar than when they insert their heads into the floral opening. Thus, nectar robbing in this species might function to reduce predation risk, although we have no data to support this speculation.