Associations of non-breeding shearwater species on the northeastern Newfoundland coast
Great and sooty shearwaters are long-distance migratory seabirds that aggregate in coastal Newfoundland, Canada, during their non-breeding season. Survey-based density and distribution of both shearwater species were primarily influenced by each other, suggesting that benefits of foraging in close association outweigh costs. The density and distribution of both species were not influenced by prey (capelin) density, but were influenced by water depth, whereby shearwaters were mainly found in shallow areas along the coast. As capelin spawning sites and migratory routes to spawning sites are located in these shallow areas (<40 m), depth (related to distance to shore) is likely an important proxy for regions of high prey availability during the summer when capelin migrate into coastal regions to spawn.