The section of Kent Island called the Shire is, like Tolkien’s Shire, filled with holes, but inside the holes are Leach’s Storm Petrels, which are nearly as endearing as hobbits. These sea birds nest in on Kent Island, and breed and lay their eggs in late May and June. They stay in their dark, earthen burrows to incubate their eggs during the day, and only hunt the ocean surface for food at night under the cover of darkness to avoid predators such as gulls and eagles.
Only a small percentage of Petrels that hatch on Kent Island ever come back to nest, and there are extensive records on the individuals that do return because they have been carefully studied on Kent Island for years. Petrels can live to be nearly 40, and Sarah expands the long-standing records of the life histories of individual birds during her daily check of each of the 300 petrel burrows. “You’re not supposed to anthropomorphize them, but you do get attached to certain birds,” Sarah explained. Her affection for them is inevitable considering that Petrels are probably the most charming creatures on Kent Island. They are extremely clumsy fliers and often crash into trees or bulldoze into their burrows, their only defense mechanisms are harmless nipping and vomiting, and their call is a gremlin-like chuckling that fills the Island at night.
Sarah is building on a Kent Island project from last year conducted by Hailey Acker and Colin McMahon, who are also Kenyon students. The first two weeks here, Hailey returned to the Island and worked closely with Sarah, showing her how to survey the labyrinthine burrows in the Shire, but now Sarah is continuing the research on her own. The project has two parts: using geolocators glued to the birds to track where they fly on their mysterious nightly foraging trips, and determining the effects of climate change on egg incubation. Sarah will artificially raise the burrow temperature by two degrees, which has been the yearly temperature increase measured on Kent Island for the past fifty years. Based on Hailey’s data from last year, Sarah hypothesizes that a raised temperature will increase the time that Petrel pairs spend on the nest, and therefore shorten the incubation time, which is normally 40 days. Because the air temperature is higher, the Petrels will expend less energy staying warm, and won’t have to forage for food as often. As Sarah put it, “they spend less calories sitting than sitting and shivering.”
While banding birds and manipulating burrow temperature may seem like relatively simple operations, the practice of fieldwork is always much more complicated and time-consuming that it seems in a neatly-written report. The Petrel project demands almost constant attention. Sarah goes out every day to check the burrows for eggs, and to weigh and measure the birds, and eventually their chicks, once they hatch in July. The Petrel measuring processes are accompanied by a terminology that is totally incomprehensible to an outsider. Before I visited the Shire, I had no idea what the “latticing” that Sarah and Hailey were constantly talking about meant, and assumed that “grubbing” had something to do with digging for worms.
My curiosity about the Shire, which seemed another world, was satisfied when I helped Sarah to survey and grub the burrows early one morning. The Shire is a magical place at any time of day, filled with trees that filter the sunlight, marshy grasses, and mosses and lichens of every shade of green. You have to be careful where you step because burrows are everywhere, marked by metal tags numbered in the order that they were found. Sarah taught me that “grubbing” actually means shoving your hand into a burrow and feeling around for a petrel, which pecks your fingers if it is home. Grubbing is dirty work, and Sarah’s arms are covered in scratches from pulling birds out of sometimes deep tunnels filled with roots. After we grubbed a burrow, we latticed it, covering the entrance with twigs that the Petrels push aside if they decide to use it, so that we would know to check that burrow for eggs the next day. The entire process took about three hours, and taught me how intensive gathering data can be, let alone the analysis that Sarah will have to conduct to draw conclusions about Petrel foraging and response to global warming. Sarah has learned that despite all of the uncontrollable variables involved in fieldwork, “you just have to do your best, and things will work out.” I certainly hope that they do, and that the next time I go grubbing, it will be for Petrel chicks.