The adult plumage consists of a sooty brown to black head, which unlike other dark hooded gulls doesn't vary by season.

The wings are dark gray with a contrasting white line on the leading edge, thought to play a function in displays and camouflage.

Young birds fledge at 55 days and continue to be cared for by the adults for several weeks.

[2] They are omnivores like most Larus gulls, generally scavenging or stealing from nests and from fishers, but will also catch fish, small crustaceans, and newly hatched lizards, iguanas, and turtles.

Potential nest predators include owls, frigatebirds and other lava gulls, as well as introduced mammals.

[2] The lava gull is categorized as "vulnerable" by the IUCN Red List because it exists in small numbers and though the population is stable, it faces numerous threats.