Observations of Hummingbird Feeding Behavior at Flowers of Heliconia Beckneri and H
SHORT COMMUNICATIONS ORNITOLOGIA NEOTROPICAL 18: 133–138, 2007 © The Neotropical Ornithological Society OBSERVATIONS OF HUMMINGBIRD FEEDING BEHAVIOR AT FLOWERS OF HELICONIA BECKNERI AND H. TORTUOSA IN SOUTHERN COSTA RICA Joseph Taylor1 & Stewart A. White Division of Environmental and Evolutionary Biology, Graham Kerr Building, University of Glasgow, Glasgow, CB23 6DH, UK. Observaciones de la conducta de alimentación de colibríes con flores de Heliconia beckneri y H. tortuosa en El Sur de Costa Rica. Key words: Pollination, sympatric, cloud forest, Cloudbridge Nature Reserve, Green Hermit, Phaethornis guy, Violet Sabrewing, Campylopterus hemileucurus, Green-crowned Brilliant, Heliodoxa jacula. INTRODUCTION sources in a single foraging bout (Stiles 1978). Interactions between closely related sympatric The flower preferences shown by humming- flowering plants may involve competition for birds (Trochilidae) are influenced by a com- pollinators, interspecific pollen loss and plex array of factors including their bill hybridization (e.g., Feinsinger 1987). These dimensions, body size, habitat preference and processes drive the divergence of genetically relative dominance, as influenced by age and based floral phenotypes that influence polli- sex, and how these interact with the morpho- nator assemblages and behavior. However, logical, caloric and visual properties of flow- floral convergence may be favored if the ers (e.g., Stiles 1976). increased nectar supplies and flower densities, Hummingbirds are the primary pollina- for example, increase the regularity and rate tors of most Heliconia species (Heliconiaceae) of flower visitation for all species concerned (Linhart 1973), which are medium to large (Schemske 1981). Sympatric hummingbird- clone-forming herbs that usually produce pollinated plants probably face strong selec- brightly colored floral bracts (Stiles 1975).
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