LOCALadk Magazine

19 Summer 2016 LOCALadk Magazine LOCALadk In late May or early June, common loon pairs build their nests in quiet, protected spots along the shores of Adirondack lakes and ponds. Collecting dead grasses and other plant material, they construct and shape their nests at the water's edge, as they do not walk very well on land. For the next month, both the male and female loons take turns incubating their clutch of one or two eggs, (rarely three) until their downy black chicks hatch and start whining for food. The incubation period comes with many stresses for loons, and plenty of hazards that might prevent chicks from hatching. Pred- ators such as mink and bald eagles will snack on eggs left unat- tended for too long (or the exposed loons themselves, in the ea- gles' case). Boating activity and wakes may force loons to leave the nest for perceived safety. Hot spells, flooding from heavy rains, black flies, and even other loons attempting to take over a territory all pose threats for nesting loons. And the list goes on…. Since 2013, the Biodiversity Research Institute's Adirondack Cen- ter for Loon Conservation has placed trail cameras at nest sites to examine these threats and loons' nesting behavior. These motion-activated cameras remain at the nests throughout the incubation period—on average snapping more than 2,000 pho- tos over the 26-28 days. Over 65,000 photos have been collected during the three years of study. This has provided a spectacu- lar window into the secretive lives of nesting loons, and has in- creased understanding of common loon behavior and threats during the critical nesting period. These photos have helped reveal the rhythm of daily life for nest- ing Adirondack loons, which often seems quite boring, as they sit patiently on the nest for hours on end. They can endure seeming- ly perpetual heavy rains that cause nests to flood, or, like many Adirondack early summer hikers, non-stop torture from black flies. Generally, a loon will sit calmly on its nest, look around, oc- casionally twist its neck and look overhead, perhaps at another loon or a bird flying by, or sometimes call out, likely to its mate. When the mate approaches the nest, the incubating loon slides off and usually takes a bath, splashing and twisting about in the water and preening intensely to cool down after having sat in the dry air for several hours before going off to feed. As the mate comes up on the nest, it raises up, propping itself back on its feet, so it can bend its beak down to turn the eggs. At this point, it is sometimes possible to see bands on the legs of the loon. (Banding is the process of fitting the loon with a small band around its leg. This band allows researchers to monitor the loons' movements and travels.) After turning the eggs, the loon then settles down over the eggs to keep them warm for the next several hours until the next mate switch. The cameras have documented surprising interactions and events. Great blue herons were frequently photographed walk- ing by the nests, and the loons remained in a normal upright position, looking calmly around. However, when mergansers or Canada geese swam near a nest, the incubating loon would lean forward into a hangover position, indicating that it was feeling threatened. If the loon had been in the water instead of on the nest, it likely would have chased the other birds away. Mammals also approached the nests – deer were frequently photographed wading in the water or walking on land, which the loons seemed to tolerate well. One night, when a large beaver climbed up and walked along the edge of one nest, the incubating loon watched it closely. The beaver just moved on, so the loon went back to its incubation duties, relatively undisturbed. At two sites, photos showed the loons wing rowing rapidly off the nest, indicating they had been suddenly startled. In one case, the photos showed three eggs in the nest as the loon wing rowed and splashed away. At the other nest, there was a lot of splashing and obvious commotion as the loon scrambled quickly from the nest. The next photo revealed a kayaker paddling close to the back of the nest, apparently oblivious to the trouble it had caused, as the nest was well hidden from view. So far, cameras have recorded 19 nests that successfully hatched chicks, and 17 nests that failed because of flooding, eggs falling in the water, predation, and other reasons. This information is vital to fostering healthy population levels for Adirondack loons and to limit anthropogenic threats to nesting success. Results from this study have already helped guide the NYS De- partment of Environmental Conservation's management of The Secret Life Of Nesting Loons By Rory Keating and photos by Dr. Nina Schoch

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