Ben West’s Black Guillemots

We sit in the grasslands at the edge of the shore on East Beach, watching the small black birds paddle, dive, and flutter in the water as the tide rises. Ben West, binoculars in hand, counts 36 floating guillemots, while twice that many herring gulls circle overhead. The guillemots make a high whistling sound that pierces through the fog, and their wings slap against the water as they take off. Black guillemots nest on Kent Island in the summer, and spend most of their lives in the water, feeding on bottom-dwelling fish. Guillemots are part of the auk family that includes razorbills and puffins, and can be identified by their black bodies with white wing patches, and most strikingly, their bright red feet and mouths. Ben tells me that they display their crimson mouths during courtship, and are faithful to their mate almost 70% of the time, which is better than most people, considering the current divorce rate.

Ben is here to find the guillemot burrows, hidden in rocky crevices and under driftwood by the shore. The guillemots are uncooperative and remain in the water, unwilling to divulge the location of their nests. Later today, Ben will build a tent-like blind out of wood that he will leave on the shore until the birds become acclimated to it. From inside the blind, he will be camouflaged and will hopefully be able to locate the birds’ nests without them being the wiser.

Ben’s project is related to the decline in global seabird populations that has accelerated over the past few decades. He is studying the effects of invasive predators on guillemots on Grand Manan, and is comparing the bird populations there to those here on Kent Island. The meadow vole and the deer mouse are the only land mammals native to Grand Manan; rats invaded from European ships, while raccoons were probably introduced to the island for hunting purposes, and have proliferated. These invasive species prey on guillemot eggs, which already have a naturally high mortality rate. Kent Island, by contrast, lacks rats or raccoons, and Ben will use the populations here as a comparison for his experiment.

His hypothesis is that there will be greater overall egg mortality on Grand Manan than on Kent Island due to rats and raccoons. Kent Island, unlike Grand Manan, has an enormous herring gull population, and rarely baby gulls stumble into guillemot burrows and crush their eggs. On Kent Island, adult black-backed gulls, which have a five-foot wingspan, sometimes swoop down and pick up guillemots for an easy dinner. Ben plans to build a fake gull colony, painted chicken eggs an all, on Grand Manan to see how the raccoons and rats respond, to help answer the question why herring gulls don’t nest there. He predicts that the guillemot burrows on Grand Manan will be farther apart and closer to the shore that those on Kent Island, because they will be built so they are harder for predators to access. If he can get a permit, Ben will weigh guillemot chicks on both islands to test the hypothesis that animals grow faster in more dangerous environments.

Ben’s experiment will require him to travel to Grand Manan once a week, a 40 minute boat ride that he must also time to coincide with high tide on Grand Manan, when the guillemots appear. While his comparative study is logistically difficult, it is a unique opportunity to discover how bird populations respond when exposed to different dangers. Guillemots are not commonly studied on Kent Island, where the focus has traditionally been on storm petrels and savannah sparrows. These endearing, red-footed birds are a new frontier for bird research that Ben will embark on this summer.

Source:

Robbins, Chandler S., Bertel Bruun, Herbert Spencer Zim, and Herbert S. Zim. Birds of North America: a guide to field identification. Macmillan, 2001.

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