Salmon scavengers are often opportunistic predators, species that feed primarily on other food sources but will take a free meal of a salmon carcass whenever they can get it. These species include voles, mink, marten, bald eagles, magpies, ravens, crows, gulls, coyotes, and wolves, among others. While larger carnivores, such as wolves and eagles, can pull live salmon from spawning grounds, smaller species rely on brown bears for their salmon supplements. Bears that drag salmon carcasses away from salmon spawning grounds to avoid competition or secret away choice morsels often leave behind partially-consumed salmon carcasses. These remains are then available to a host of scavengers as a free meal.
Relatively little is know about the extent to which smaller carnivores depend on salmon for subsistence. Since species like mink and marten can’t actively secure salmon for themselves, it is unlikely that they depend solely on salmon as a food source. However, in areas with a lot of bear activity or when runs are particularly strong, a larger proportion of these smaller carnivores’ diets may be composed of salmon. Our research group hopes to determine how often scavengers feed on salmon carcasses, and how much they may or may not rely on salmon subsidies as a food source.
If you’re interested in seeing additional photos of scavengers, check out the following blog posts, with series of images captured by our motion-detecting trail cameras: