Gregory is a wildlife ecologist with specialized experience in research and conservation management of seabirds. He has studies seabirds in Hawaii, Alaska, and Antarctica both at sea and on the breeding colonies and is particularly interested in foraging ecology, adaptation mechanisms to cope with ecological stressors, species recovery, and restoration ecology. He has been involved in work to examine the ecology and conservation needs of Newell's shearwaters and Hawaiian petrels since the early 1990s and enjoys developing practicable management actions that result in measurable and sustainable conservation benefits for rare and threatened species.