Instinctively you recognize the call of a loon: it is unforgettable. But what you may not know is that loons have four distinct types of calls.

Most likely, you are most familiar with the wail or tremolo. The wail, which sounds like the howl of a wolf, is most frequently given in the evening or at night and can be heard for many miles. This haunting call is used to keep in contact with other loons. The tremolo has been described as “insane laughter;” it is 8 to 10 notes voiced rapidly. This alarm call usually indicates agitation or fear.

What you also may not know, is that the loon is an indicator of water quality.

Although loons look duck-like, they are truly a “bird of a different feather.” Loons, aka “northern divers,” are well-constructed diving machines. First, they do not have hollow bones as other birds do. Their more solid bones enable them to dive deeper and stay submerged longer in search of underwater food.

Denser bones are, however, heavier and therefore loon flight is much more clunky than other birds. They are also much bigger, weighing somewhere between 6 to 13 pounds, compared to the common merganser [duck] which typically weighs between 2.5 to 4 pounds. Also loon legs are located far back on the body, leaving the bird top and front heavy and unable to walk well on land. However, the large webbed feet and position of legs generates a lot of underwater power. Loons are known to dive to 200 feet and can remain underwater for five minutes.

All these unique physical characteristics lead to the need for remote breeding areas. Common loons breed in northern America and nest on the ground along lake shorelines during May and June. Their nest must be close to water, as loons are clumsy and slow on land. Ideal habitats for breeding are clear freshwater lakes with plentiful fish, undeveloped or vegetated shorelines, deeply indented bays, numerous islands, floating bogs and surrounding forest. Sebago Lake offers many excellent loon breeding areas.

Sebago Lake supports a healthy population of loons, but they are vulnerable to the threats of overdevelopment, lead fishing sinkers, mercury deposition, and declining water quality. All of us play an important role in protecting these magnificent creatures so we can continue to enjoy their haunting calls and distinguished presence.

5 ways you can help

1. Take part in the count: Each year, Portland Water District coordinates the Sebago count for Maine Audubon’s Annual Loon Count on the third Saturday in July. Sebago volunteers have documented between 4 and 15 loons on Loon Count day, but more volunteers are needed to cover a greater percentage of the lake. To volunteer, contact Nate Whalen at [email protected]

2. Enjoy at a distance: Please stay away from loon nests. Loons do not like boat traffic or being approached by humans. They may even abandon their nest if disturbed.

3. Be a responsible angler. Fishing gear poses problems for loons. Every year, loons in Maine die after becoming tangled in fishing line. Lead poisoning from lead sinkers and lead-headed jigs is the leading cause of death for adult loons in Maine.

4. Reduce polluted run-off: Loons, fish and people rely on clean water to survive. Use phosphate-free detergent and fertilizer and clean up after your pet.

5. Learn more: To learn more about loons and the Sebago Loon Count, the Portland Water District will host “The Common Loon, Symbol of Maine Wilderness and Indicator of Lake Health” by wildlife biologist Camilla Fecteau. The presentation will be on July 14 from 6:30 p.m. -8 p.m. at the Sebago Lake Ecology Center. Space is limited, register today at [email protected]

The Water Resources group at the Portland Water District also has a blog, “Reflecting on Sebago,” which can be viewed at