Naturally Kiawah Magazine Volume 38 | Page 51

Beyond their need to replenish lost body weight, these visitors need to regroup, take a breather, and enjoy significant down time before taking back to the sky. But how exactly does a shorebird rest? It’s not like they string up a hammock and sleep for three days before moving on. It takes weeks and months to regain their strength. Often arriving on our beach in March and staying into May, these visitors seek peace and quiet. But rest for a shorebird can prove elusive, partly due to their own habits and partly due to human interference in their natural habitat. The very nature of a shorebird’s feeding is counter to their need for respite. Shorebirds feed on the open sand, in full view of dive-bombing raptors looking for their own dinner. As they hunt for food, they must be constantly aware of becoming the hunted. In addition to the risks from above, shorebirds must be cognizant of intruders on the ground. Running dogs and approaching people are beyond bothersome; they rob the shorebirds of rest. Anytime a dog or person gets too close, shorebirds will scatter to avoid the perceived danger. While they can easily dodge such ground-based trespassers, they must expend energy to do so. Unfortunately, for a bird that needs to rest, any added or unnecessary flight is counterproductive. Do these remarkable birds actually ever sleep? Well, yes, although it is likely a light sleep, easily interrupted by sound or motion. Beyond the traditional closing of both eyes and drifting off to a semi-conscious slumber, many shorebirds have a unique ability to close only one eye at a time, while keeping their other eye open. Unihemispheric slow-wave sleep (USWS) allows birds to shut down one-half of their brain, putting it into a deep sleep, while the other hemisphere of their brain remains awake. Many animals possess this ability, including bottlenose dolphins, beluga whales, ducks, and even crocodiles. Humans do not have this ability, as evidenced when we try this trick during commercial breaks while watching late-night television, only to wake up several hours later to an infomercial for the most powerful blender ever created. For shorebirds, USWS provides them the rest they need while allowing them to be aware of predators and other threats to their well-being. When resting on the shore, the birds will remain still with their open eye facing the direction most likely to hold danger. When done in mass unison, this phenomenon is referred to as “group edge effect”. The study of USWS continues to evolve, and not every aspect of it is understood today, but this ability possessed by many shorebirds helps them tremendously in their quest for rest. With fattened bodies and strong wings, these amazing little fliers will leave as a group, continuing north to their Arctic nesting grounds. Stopovers further up the coast, such as the Delaware shore, are common before they complete their journey. In the cold they nest and welcome their offspring, then travel south again to start the cycle anew. A typical shorebird will make this trip a dozen or more times during its life. These annual flights are a remarkable accomplishment for such small animals, a tribute to their energy and strength. NK How can we help shorebirds get the rest they need? Some simple rules: • • Do not let pets or children approach Least tern. SUMMER/FALL 2017 • VOLUME 38 the birds as they are resting. A shorebird who flies away is not resting. • • Stay away from feeding areas and any designated nesting zones. • • If you hear the birds s creaming or making loud noises, leave the area. They are trying to tell you that you are too close. • • Stay away from the tips of the island and any remote sections of the beach. • • Pick up your trash. 49