Resumen

In Manu National Park, Peru, I investigated feeding behavior, bird activity on and seed dispersal of two sympatric Neotropical rain forest trees, Guarea macrophylla and Trichilia quadrijuga. The numbers of individual visitors, visiting species, and seeds removed were directly correlated to the available fruit crop for each plant species. Of 18 bird species which consumed Guarea fruits, only Swainson’s Thrush (Catharus ustulatus), Sulphur-bellied Flycatcher (Myiodynastes luteiventris), Blue-crowned Manakin (Lepidothrix coronata), and Band-tailed Manakin (Pipra fasciicauda) consistently visited and dispersed its seeds. Of three bird species which consumed Trichilia fruits, only Band-tailed and Roundtailed Manakins (P. chloromeros) regularly visited and dispersed its seeds. Variance in the time spent at fruiting trees across and within bird species was high. Most bird activity occurred between 07:00 h and 10:00 h. With few exceptions, all visiting birds perched in the observed tree and then removed fruit either in flight or by reaching from a nearby perch. The number of ingested pulp units per visit ranged from zero to six depending on the bird. Few seeds were dropped under the parent tree. Accepted 25 February 2014.