In addition to seed deposition of both native and invasive plant species, birds may pollinate flowers, provide nutrient inputs, and deliver mutualistic or pathogenic microbes. Birds therefore may drive community assembly and succession, and play an especially significant role in the frequently-disturbed environments of barrier islands, where repopulation following storm and overwash events is critical to long-term species persistence. We investigated bird dispersal of seeds to grass- and shrub-dominated patches of the island landscape, and the possible avian introduction of nitrogen-fixing Frankia bacteria. Artificial perches with attached fecal collectors were erected on three islands of the Virginia Coast Reserve, a long-term ecological research (LTER) site, and periodically checked for evidence of use. Contents were emptied into sealable plastic bags and returned to the laboratory for evaluation. Seeds were identified and stored as a reference collection. Woody species within 10 m of perches were also identified. Patterns of seed deposition indicated that spatial variation in island topography, vegetation structure, and island position were important to seed dispersal. In addition, experiments tested for the presence of N-fixing nodules when sterile Morella cerifera seedlings were exposed to fecal material. After 5 to 7 weeks of seedling growth following inoculation, plants were uprooted and evaluated for the presence of nitrogen fixing nodules. Results indicated that birds act as dispersers for the bacterial symbiont, providing both the primary and secondary requirements (seed arrival, and bacterial introduction, respectively) for M. cerifera colonization, a tipping point in the successional development of plant communities of many of these islands.