Role of Alien and Native Birds in the Dissemination of Firetree (Myricafaya Ait.-Myriacaceae) and Associated Plants in Hawaii

Abstract

The food habits of several forest birds and their potential role in the dispersal of firetree (Myrica faya) were studied in two areas of Hawaii Volcanoes National Park. Observations were made during peak firetree fruiting (October-November 1983) in areas where 'ohi'a (Metrosideros polymorpha) and firetree are codominant. Both native and introduced birds foraged in firetree and 'ohi' a, but introduced birds were more common in firetree. Ofthe six bird species observed, 'oma'o (Phaeornis obscurus) and house finches (Carpodacus mexicanus) were the principal dispersal agents in the areas studied, while the common 'amakihi (Hemignathus virens) was secondarily important. Japanese white-eyes (Zosterops japonicus), though feeding on the fruit, rarely ingested the seed. 'Apapane (Himatione sanguinea) and Northern American cardinals (Cardinalis cardinalis) were not observed eating firetree fruit. Germination rates and successes of several native and alien species are generally unaffected by passage through the digestive tracts of captive Japanese white-eyes and common mynas (Acridotheres tristis).