The project will study the effects of human changes to the environment on the demography of storm petrels. These human influences include, beside others, light pollution (storm petrels are strictly nocturnal as a defense against diurnal predators) and altered predation rates due to increases in number of predators. These altered predation rates occur when, for example, scavenging seabirds (such as gulls and skuas) are forced to switch diet to predation as a consequence of reductions in discarding by fisheries. Storm petrels are also highly vulnerable to introduced mammals (rats, cats). Many of these small seabird populations are vulnerable to the effects that result from human activities, and conservation of storm petrels requires better understanding of impacts and measures that can be taken in mitigation. We will study several colonies of storm petrel species to compare these direct and indirect human effects. Although patterns on predation have been described, the quantitative relationship between human activities and predation impacts are not known. The project will quantify this relationship, and will analyze demographic parameter of storm petrel populations and resulting populations trends as a consequence of predation impact.