Birds have been referred to as “bellwethers of watershed health” because they respond to basic changes in landscape and habitat conditions.Roger Tory Peterson, an American naturalist who published many books about birds and garnered multiple awards in his field, once said, “Birds are an ecological litmus paper. Because of their rapid metabolism and wide geographic range, they reflect changes in the environment quickly, and they warn us of things out of balance, sending out signals whenever there is deterioration in the ecosystem.”
GLA’s Watershed Biologist Rob Karner, a former ornithology instructor, monitors the variety, patterns, and health of area birds as potential leading indicators of overall watershed health. The robust diversity and health of our year-round resident birds and migratory birds point to a healthy watershed, and we felt it was important to introduce you to some of them. We hope you have enjoyed our series — share it with friends and family so we can all be a little more connected to our beautiful watershed and the creatures that live in it.
You may have heard the distinctive calls of common loons echo across Glen Lake. They can be very vocally active with nocturnal choruses. After sundown, the lake often reverberates with the echoes of loon wails and yodels and tremolos (which writer John McPhee called “the laugh of the deeply insane”). Listen to a loon here: https://www.allaboutbirds.org/guide/Common_Loon/overview
Common loons spend a lot of their time working shallow waters for fish: swimming slowly and sticking their heads into the water to look for fish, then diving suddenly, hardly leaving a ripple on the water’s surface. Loons do all their feeding during the day, when they can best see their prey. A hungry loon family can put away a lot of fish – biologists estimate that loon parents and their two chicks can eat about a half ton of fish over a 15-week period.
Loons are well equipped for their submarine maneuvers to catch fish. Unlike most birds, loons have solid bones that make them less buoyant and better at diving. They can quickly blow air out of their lungs and flatten their feathers to expel air within their plumage, so they can dive quickly and swim fast underwater. Once below the surface, the loon’s heart slows down to conserve oxygen.
At times, loons can be seen sticking one foot up out of the water and waggling it—this may be a means of cooling off, as scientists have observed loons waggling their feet more often on sunny, midsummer days. Loons also perform a territorial display of lifting their body upright and flapping their wings vigorously. Canoeists or kayakers who get too close to a loon may witness this display, along with a defensive tremolo call as the loon swims away.
Loons are like airplanes in that they need a runway for takeoff; they need from 30 yards up to a quarter mile (depending on the wind) for flapping their wings and running across the top of the water in order to gain enough speed for lift-off. When loons fly, their necks stick straight out and their feet trail behind them. Loons are agile swimmers, but they move quickly in the air, too – migrating loons have been clocked flying at speeds more than 70 mph.
In spring, loon mates arrive back on their lake separately. Loons are monogamous, and pair bonds typically last about five years. If one of the mates doesn’t return in the spring, the other will quickly pair up with another mate.
The male defines his territory through yodeling. Courtship consists of swimming in circles and synchronous dives. If nesting is successful, loon chicks can be seen going for a ride around the lake on a parent’s back.
Loons are water birds, only going ashore to mate and incubate eggs. Their legs are placed far back on their bodies, allowing efficient swimming, but only awkward movement on land.