Dispersal of Cayratia japonica Seeds by Birds in an Urban Green Space in China

Frugivorous birds play important roles in seed dispersal. In this study, we assessed the contributions of bird functional traits (behavioral traits: foraging quantity, number of birds per visit, and foraging duration; morphological traits: weight and body, wing, and tail lengths) to both seed removal patterns and dispersal distances of Cayratia japonica in an urban garden in southwest China. Eleven bird species were recorded feeding on its seeds, and eight bird species were confirmed to be seed dispersers. Oriental turtle-dove (Streptopelia orientalis), red-whiskered bulbul (Pycnonotus jocosus), and red-billed blue magpie (Urocissa erythrorhyncha) were the main seed dispersers. The number of seeds removed increased with bird foraging frequency, and seed dispersal distance increased with bird body and tail lengths. Our results highlight the importance of bird functional traits in seed dispersal patterns of C. japonica, which should be considered for tree management.