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n an early morning in late May we launched our kayaks and headed out around Trinidad


Head. The ocean was glassy in the early morning hours. We expected that later in the day the winds would begin blowing from the northeast, as they often do in the afternoons over the waters off the Humboldt County coast. A raft of several hundred Com- mon Murres (scientific name: Uria aalge) bobbed with the ocean swell in the shoal between Flat Iron Rock and Trinidad State Beach, just north of the head- land. As we paddled closer, the fresh aroma of the marine air was invaded by an overpowering and unmistakable stench of guano.


The raft of murres was actively vocal- izing, diving amongst the brown kelp and surfacing as long as a minute lat- er with small silver fish firmly locked in their bills. The fish were hard to identify, but were probably some kind of smelt or juvenile rockfish. Some of the birds flapped their small and nar- row wings furiously as they attempt- ed to take flight and return to their nests on the rock in order to feed the fish to their chicks. It was not the raft of birds that smelled so pungent, but rather the white guano-stained Flat Iron Rock.


Flat Iron is one of several sea mounts along the northern California coast that serve as critical nesting habitat for a variety of sea birds like murres and cormorants, as well as being resting sites for Brown Peli- cans. The distance of the rock from shore and its steep entrance into the water render it inaccessible to most land-based predators, afford- ing protection for eggs, chicks, and adults alike. At Flat Iron Rock, the most prominent residents, by sight or smell, are the thousands of Common Murres. In fact, Flat Iron alone has more than 12,000 pairs of nesting murres. The murres are charac- terized by their highly contrasting brownish-black backs and heads and bright-white undersides. The murres


nest on Flat Iron from late April to early July in most years, but they start extended visits to claim their ex- act nesting site in February or earlier each year.


In the case of murres, the word “nest” does not describe what most people might picture in their minds as a bird nest. Each pair of murres lays a sin- gle blue-green egg among the rocks; no sticks or nesting material, just hard rock. With luck, they choose a site where their egg will not roll away, be trampled by their neighbors, or be stolen by a gull or raven for lunch.


There are relatively few large rocks, sea stacks, or sea mounts that can be used for nesting. For those that are suitable for nesting, the availabil- ity of specific sites where the terrain is flat enough to prevent eggs from rolling away, or protected from waves or ocean spray are in limited sup- ply. This, in part, causes the murres to nest in tightly packed groups. A more important reason, however, is that there is safety in numbers that benefit both chicks and adults. The chicks and eggs on the edge of colo- nies suffer predation from gulls and ravens. Adults, too, can be vulner- able to eagles and falcons.


Common Murres grow to 18 inches in length, 29 inch wingspan, and weigh about 2 pounds. Male and female murres are indistinguishable. Photo courtesy of USFWS/ Humboldt State University


There is also a downside to living so close to your neighbor. When they bring a fish for their chick, they must land within the colony of birds and get the fish to the chick without the catch being stolen by another murre or resident gulls. Murres work hard for their fish, often diving to hundreds of feet below the surface. If fish are stolen or lost, it not only deprives the chick of a meal, but the parent loses a lot of time and energy that it had spent finding, catching, and air- freighting the fish back to the rock.


Murres also share the rock with larger, more aggressive cormorants. Two species of cormorants, Brandt’s Cormorants and Pelagic Cormorants, nest on the rock. Unlike murres, Brandt’s Cormorants build substantial nests of sticks and are very aggres- sive towards any intruder. Brandt’s Cormorants’ nests are widely spaced across the rock, and no bird will ven- ture within a necks-reach of a cor-


California Kayaker Magazine 11


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