Foraging behavior of Purple-rumped sunbird (<i>Leptocoma zeylonica</i>) and Long-billed sunbird (<i>Cinnyris lotenius</i>) in selected habitats in Kandy district, Sri Lanka

Abstract

Sunbirds (Passeriformes: Nectariniidae) are small passerines that feed largely on nectar. The aim of this work was to study the occurrence of sunbirds in different habitats, to observe and describe their activity frequencies, to observe the relationship of the Long-billed sunbird Cinnyris lotenius and Purple-rumped sunbird Leptocoma zeylonica with their host flowers, and to examine their behavioral relationships with the colour of the flower, flower count, nectar glucose concentration and the length of corolla of flowers. The study was carried out in five different habitat types in the Kandy district, Sri Lanka: a forest reserve, home garden habitats at two widely separated locations, a roadside habitat, and a botanical garden. The study was carried out between March and September 2013. Results show that during the day, sunbirds spent most of their time in foraging than in acquiring food. In the study, 21 different plants were recognized as nectar feeding plants for sunbirds. The number of visits by sunbirds did not depend on the plant species or the colour of the flower. The results also indicated that the correlation between the flower count and the occurrence of the Long-billed sunbird was not significant. However, there was a significant correlation between the flower count and the occurrence of the Purple-rumped sunbird. Furthermore, there was a significant correlation with the glucose concentration and the occurrence of the Long-billed sunbird; whereas no such correlation between the glucose concentration and the occurrence of Purple-rumped sunbird. There was no significant correlation with the length of corolla and the occurrence of the Long-billed sunbird, but there was a significant correlation in occurrence of Purple-rumped sunbird and the length of corolla. These correlations are due to the difference in their body size and bill length. The difference in feeding plants is due to their bill length and that allows both of them to share a common habitat.

Keywords

• sunbirds, occurrence, behavior, correlation, habitat