The Common Loon:
The Iconic New Hampshire Bird Catherine Greenleaf - Lyme, NH
W
hat could be more primal than the call of the loon? The loon’s alluring and bewitching cry sends shivers up my spine every time I hear it. The Common Loon (Gavia immer) is a beautiful yet formidable creature, often referred to as a “torpedo with wings” because of its incredibly fast diving and flying abilities. There are no wild animals foolish enough to approach this apex predator, since its sharp, lightning-fast beak and aggressive fighting tactics usually place the loon squarely on the winning side of any altercation. Territorial disputes between loons often end in fatalities. EXPERT DIVERS Closely related to the penguin and the albatross, the loon has solid bones, which makes the bird less buoyant and better at diving. When loons dive they blow the air out of their lungs and flatten their feathers to expel pockets of air within their plumage, allowing them to descend quickly. Remarkably, a loon can dive up to 200 feet under water. The loon has a unique internal blood gas exchange system that allows it to dive deeply and ascend quickly, without suffering what human divers would call decompression sickness. CARNIVOROUS BIRDS Loons prefer to eat fish, mostly perch, trout, smelt and minnows. But they will also eat frogs, crayfish, salamanders, and leeches. At the end of summer, the loon migrates to the open ocean, where it spends the winter eating fish and crustaceans along the New England and New Jersey coastlines. The loon has a special salt gland located between the eyes. This gland can shut 50 4 Legs & a Tail
on and off at will, allowing the bird to safely ingest salt water in the ocean without suffering any ill effect. LOONS CAN’T STAND UP A loon’s legs are set far back on its body and are essentially useless on land. A loon cannot stand up on its legs and walk but must drag its body to move across solid ground. At nightfall, exhausted loons may land on the ground if water cannot be found, and rain and fog can make asphalt parking lots look like water from above. There are reports of loons dragging their bodies through miles of forests to find water. Loons need a long runway to take off into the air. Ideally, they need at least a ¼ mile (400 yards) of open water in order to achieve lift-off. They run across the surface of the water with their webbed feet to gain momentum, flapping their wings until they become airborne. A THREATENED SPECIES The loon is listed as a Threatened species in New Hampshire. Loon survival is challenged by neurotoxic poisoning from lead fishing tackle, entanglement in fishing line and chick and egg predation by other wildlife. Unfortunately, there is yet another danger forming for the loon. LONGSTANDING MYSTERY New laboratory findings have brought an end to a longstanding mystery over why loon eggs have not been hatching on Sqaum Lake. Last year, the Loon Preservation Committee in Moultonborough ordered a series of tests on 81 failed loon eggs collected from 24 New Hampshire lakes over the last ten years, the majority of which came from Squam Lake. Sixty percent of the eggs were found to contain toxic contaminants in levels
high enough to cause negative reproductive effects in bird species, according to the LPC’s formal report issued at the end of last year. The tests found significant levels of contaminants like PFAS (stain resistant chemicals) and PCBs (chemicals once widely used in electrical equipment). The tests also revealed alarmingly high levels of polybrominated diphenyl ethers, a class of flame retardant chemicals better known as PBDEs. Despite some of these chemicals having been banned for over 40 years, they are still being detected in wildlife. The reason? Scientists speculate these harmful chemicals reside in the sediment at the lake’s bottom. The sediment is consumed by insects, which are then eaten by fish. The concentration of the chemical increases as it moves up the food chain. Scientists also suspect toxins, like flame retardant chemicals used to treat children’s clothing, are seeping out of septic leach fields and finding their way to streams and lakes. A contaminant can be present in fish at a concentration much higher than its concentration in the water, according to senior biologists at the LPC. Sadly, these contaminants are “forever” chemicals, since nature is unable to break them down, and will therefore always remain in the water. How the population status and health of the loon will be affected over the long term by these chemicals is a big, unanswered question, and the subject of multiple, ongoing studies at present. Catherine Greenleaf is the director of St. Francis Wild Bird Center in Lyme, N.H. If you find an injured bird or turtle, please call (603) 795-4850. Spring 2022
