What kills seabirds and marine mammals?
There are both natural and un-natural mortality factors. The natural causes of death for seabirds and marine mammals are starvation, disease, and predation (e.g. shark bite). Unnatural causes of death are oil spills, entanglement in fishing line or nets, boat strike, gun shot, and other human-related causes. Oil spills kill greater numbers of seabirds than mammals because oil affects their ability to keep warm. Seabirds depend upon their feathers as insulation and get hypothermic (lose body heat quickly) when oiled. Diving birds, such as murres, loons, and grebes, are particularly vulnerable to oil spills because they cannot walk well on land and stay at sea. Pelicans and gulls that are fed by humans get very tame to people on wharfs and fishing piers and often get tangled in fishing lines. Seabirds and mammals also may be attracted to fish lures, thinking they are fish. Surface feeding seabirds such as albatross and shearwaters mistake plastic for food and consume these unnatural item
