Endangered Species Report #36
Common Loon

Written by: Holly L. Koppel

On a cool summer night, the haunting call of a rapidly disappearing species can heard for miles around the New England coast. People's ears prick up at the sound, while tourists smile, knowing that their dream of hearing the call of the common loon has been realized. What they don't realize however, is how they are contributing to the decline of this species. In years past, one could hear this call with much frequency throughout New England, but now the only place you can go where the loon is not in serious danger is the coasts of Maine.

Habitat loss and human disturbance of nesting sites are amongst the top two threats to the loon's survival. The third threat to their survival is currently being studied by the Environmental Protection Agency (EPA). Objectives of this study include: random sampling of the current breeding population to calculate the population density, and the other objective is to quantify the impact of multiple stressors on this population. The stressors they are studying include: high mercury levels in the water, habitat alteration, predation, and human disturbance. So far, the study has found that elevated mercury levels have slowed down chick development, leading to baby loons spending less time with their parents, and leaving the nest too early to survive. This makes them very vulnerable to predators, such as the raccoon, fox, hawk, and humans. Frequently, baby loons are killed by jet skis going by on lakes they inhabit. Scientists are currently looking into the effects of the other stressors on the population, as well as ways to decrease the amount of mercury in the lakes and rivers.

Another threat to the survival of this species is habitat destruction. Loons prefer large, clear northern lakes, and marshy areas with small islands and plenty of fish. Unfortunately, humans also like this kind of habitat, and over the past 20 years, lakeshore developments have cropped up all along the New England coast, as these states promote themselves as the perfect summer retreat from the bustle of city life.

These lakeshore developments have made many areas unsuitable for loon breeding, as loons usually nest right next to the water, so that they can just scoot into the water to feed. Usually when nesting, the female will lay two brown spotted eggs, with the first being the bigger of the two, and both the male and female will incubate the eggs for about one month, making sure that the eggs are covered 99% of the time.

After the eggs are hatched, the babies will be fed by their parents for about eight weeks at which time, they will start diving for their own food. By 11-13 weeks of age, the chicks can feed themselves, and they have learned how to fly. The loon family will stick together for the remainder of the summer until winter migration, and then they will head off for the southern coastal waters. The loons usually will return to the same lake year after year to nest, and if left alone by humans, the loons will live about 15 to 30 years.

Unfortunately because of human interference around the lakes, a lot of loon parents have been forced to abandon their nest sites in search of areas with a lower concentration of humans. Because of this, there are now 35% fewer loons in New York than there were just 25 years earlier. At last count in Maine, there were only 3,949 loons left, and this is the largest count in all of the New England states.

Steps are being taken now to help save this species and to restore their original habitat. The Vermont Loon Recovery Project (VLRP) has been working with over 10 lake associations, distributing loon fact sheets and holding meetings. They have also participated in management programs to create and place nesting platforms on lakes that loons are known to inhabit. So far, these platforms have been successful. In the year 2000, 17 of the 38 nesting pairs used these platforms for nesting, and more are expected to use these in the future.

Despite this success, there is still one more threat to the loon that looms. Since loons are diver birds, meaning that they dive into the water to chase after fish (which are their main diet), they sometimes swallow lead sinkers left behind by fisherman. This is very hazardous to the bird and leads to lead poisoning which has wiped out a good portion of the species. The VLRP is currently working to curb this threat by educating fisherman of this danger, and also sponsoring a sinker exchange program.

Despite the mounting threats to the common loon's survival, many of the New England states have stepped up to the plate by declaring the loon threatened or endangered. Currently, the loon is listed as a threatened species in Michigan and New Hampshire, and it was declared endangered by the state of Vermont in 1987. The loon is also a federally protected species in Canada; however, the U.S. Fish & Wildlife Service has yet to declare the loon threatened or endangered in the United States.

If we have any hope of keeping this species around for our children to enjoy, the plight of the loon must be recognized by all the countries where it can be found. In addition, lakeshore development must be curbed, and strict laws put in place to ensure this species' continued survival. Only then, can we have any hope of continuing to hear this bird's haunting call echoing throughout the New England wilderness.


Animal Diversity: Common Loon Narrative
Canada Wildlife Service—Loons
Audobun International Common Loon Factsheet
Evaulating the Impact of Multiple Stressors on the Common Loon Population
Vermont Loon Recovery Project
Adirondack Info on Loons
Maine Audubon Society
Common Loons in Canada by Joe Kerekes
Loon Preservation Committee