It resembles the closely related Scripps's and Craveri's murrelet, with which it shares the distinction of being the most southerly living of all the auk species.

After the breeding season it disperses locally at sea northward up to southern California in the United States.

It nests in small crevices, caves and under dense bushes on arid islands in loose scattered colonies.

By the end of the 20th century, the Xantus's murrelet complex was considered to be among the most endangered group of auk.

Guadalupe murrelet is mainly threatened by oil spills, as much of its population lives near the busy shipping lanes connecting Los Angeles to other ports.