Los Farallones

Dispatches from Point Blue’s field station on the Farallon Islands National Wildlife Refuge

The Ghost Murre

The Farallon Islands are home to one of the largest aggregations of breeding seabirds in North America south of Alaska, with the Common Murre (Uria aalge) being the most abundant, reaching numbers upwards of 300,000 individuals during the peak breeding season. To the unfamiliar eye, one might look at a murre and mistake it for a penguin, and they would be forgiven for thinking so. Common Murres are, rather, a member of the alcidea family and often referred to as the “penguins of the north”. Similar to many penguin species, Common Murres appear to be wearing tuxedos, with a coat of black feathers on their head, back and wings, with a pale white belly and underwings, as well as a black pointed bill. Like many other seabird species and other pelagic animals, the Common Murre’s plumage coloration is an example of countershading, where they have a light-colored ventral side and a dark-colored dorsal side. This type of coloration is an effective form of camouflage in marine environments, making it more difficult for predators from below to detect them in sunlight, and likewise more difficult for predators from above to detect them on the dark ocean. Some predators, like killer whales (Orcinus orca) or white sharks (Carcharodon carcharias) are also colorshaded, to a devastating effect against their prey.

Close up of Common Murres in their typical breeding plumage. March 17th, 2021. Photo by James Lee, Point Blue Conservation Science.


On the morning of April 9th, however, one of our volunteer seabird research assistants, James Lee, spotted an abnormal looking murre while performing band resighting for Brandt’s Cormorants. This murre’s back was a faint black color with white speckling throughout, its belly and head were white, and its bill a pale orange. Immature and non-breeding murres will usually lack the clean “tuxedo” appearance of breeding adults, instead appearing whiter on their faces and sides. But this adult bird was clearly an aberrant individual, standing out starkly among the huddled flock of murres in their breeding plumage.

A leucistic Common Murre. April 9th, 2021. Photo by James Lee, Point Blue Conservation Science.


One might be quick to say that the murre exhibits a form of albinism, which would not be accurate. Albinism refers to the lack of the pigment melanin in an individual, which would result in the lack of any dark coloration whatsoever, thus the presence of some black on its back disqualifies it from being truly albino. Instead, this individual is leucistic, meaning that it exhibits a partial loss of melanin pigmentation (also referred to as “piebald”), as opposed to a total loss of pigmentation in albino individuals. While albinism and leucism can be somewhat common among domesticated animals, seldom is it observed in wildlife populations, as light-colored individuals are often easily spotted by predators and quickly dispatched. Common Murres on the Farallones in particular are a favorite meal of Peregrine Falcons, and are also predated upon opportunistically by pinnipeds (seals and sea lions) and owls. The fact that this individual was able to survive into adulthood in apparently healthy condition is incredible, and a rare treat for researchers to observe. And so sat that pale murre like a ghost on the rocks.

By James Lee