DISSERTATION RESEARCH: Do mesoherbivores drive Neotropical rainforest understory insectivorous bird declines by limiting availability of preferred foraging microhabitat?

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Tropical birds are highly vulnerable to forest fragmentation, and declines are often attributed to the direct effects of decreased habitat size. However these birds have nearly disappeared from some large forest fragments, but persist in smaller nearby reserves. Mechanisms other that habitat size proposed to account for these declines (food-limitation, dispersal-limitation and nest predation) also fail to explain the puzzling patterns observed in several tropical forests. The proposed research investigates a new, alternative hypothesis to account for bird declines in large habitat patches that has three key components: (1) understory insectivorous birds prefer to forage in dense woody vines called lianas; (2) collared peccaries suppress liana densities, and (3) loss of suitable habitat and, consequently, bird populations correspond with peccary densities. The study will test the three components of this hypothesis in central Panama, where both focal bird populations and lianas have increased while peccary densities remain low.Results from this project have immediate conservation applications in reserves across Central America. The graduate student involved is bilingual and plans to engage local land owners and managers in Panama in the project. Outreach to local communities will include bird identification and bird banding demonstrations. Undergraduate students from groups typically underrepresented in science will also be trained through participation in this research.