Fruits have evolved as a means for plants to disperse their seeds. The progeny of a zoochorous plant that is unsuccessful in attracting animal dispersers will likely have lower survival than a plant of the same species that does attract dispersing agents. Tightly coevolved frugivore-plant systems are relatively rare, but a bird-plant interaction in Papua New Guinea offers special opportunities for such a study. The dwarf cassowary (Casuarius bennettii) is frugivorous and may be the sole disperser of many large-seeded plant species in New Guinea. One hundred twenty 50 x 10 m transects are to be monitored monthly for the purpose of quantifying crop parameters, fruit characteristics, and phenological patterns. Scats are to be analyzed to compare cassowary diet with fruit availability on the transects. An effort will be made to determine the most important factors determining cassowary fruit choice. Using manipulations (such as exclosures), fruit traps, and observations, it will be possible to ascertain whether these large birds are the sole consumers or sole dispersers of their primary food plants. Radio-tracking is to be utilized in order to learn about ranging patterns, habitat use, and specific foraging movements. Finally, this information is to be used in conjunction with floral comparisons to estimate the importance of cassowaries to the evolution and maintenance of New Guinea's flora.
