Birds Visiting Flowers of Erythrina suberosa: Their Abundance, Frequency of Visits and Role as Pollinators in a Sub-Tropical Montane Forest of Garhwal Himalaya

ABSTRACT Bird pollination is specific among flowering plants which support mostly cross pollination and has been regarded as an important pollination syndrome. Frequency of bird pollinators visiting flowers of the corky coral tree Erythrina suberosa Roxb., was studied in a subtropical montane forest located in Garhwal Himalaya, India. Forty trees were selected randomly in the population and the observations on birds visitors were recorded for 10 days during peak flowering. In total 18 bird species were found visiting flowers of E. suberosa. The bird species belonging to Passeriformes, Piciformes, Psittaciformes, and Cuculiformes were observed most frequently. The highest bird frequency and abundance among flower-visiting birds were recorded for the red-billed blue magpie Urocissa erythrorhyncha (26 ± 3.2 individuals per hour per branch and 60 birds per tree, respectively), whereas the lowest – for the verditer flycatcher Eumyias thalassinus (2 ± 0.02 individuals per hour per branch and 6 individuals per tree, respectively). Majority of the bird species followed bimodal pattern of foraging on nectar in a day (mostly morning and evenings), which is consistent with other studies carried out for other ornithophilous tree species in the Himalayan region. The birds observed in this study are presumed to be pollinators, as the majority of birds foraged on nectar of properly opened flowers oriented upwards; however, possibility of nectar robbing cannot be excluded and requires further investigation in future studies.