Organisms with limited motility may use animal transport as a mechanism for dispersal. Migratory birds can provide a vehicle to move small organisms great distances, which may allow them access to areas that are otherwise inaccessible. During normal mist netting operations at a spring migration banding station along the northern Gulf of Mexico coast in Louisiana, USA, we encountered an Indigo Bunting (Passerina cyanea) with numerous snails, possibly Galba cubensis, underneath its breast feathers. While encounters of songbirds carrying snails appear rare, long-distance migrating songbirds represent a possible mechanism to transport small snails great distances to expand ranges, colonize new areas, or maintain genetic continuity.
Zenzal, T. J., Lain, E. J., & Sellers, J. M. (2017). An Indigo Bunting (Passerina cyanea) Transporting Snails During Spring Migration. Wilson Journal of Ornithology, 129(4), 898--902. https://doi.org/10.1676/16-182.1