Common Name Common Loon
Scientific Name Gavia immer
Other Names Great Northern Diver
General Appearance: In summer, both male and female Common Loons have black heads that appear almost iridescent, red eyes, a long dark pointed bill, a white necklace around the black neck, and white spots on a dark black back and sides. The Common Loon has a white breast and belly, with dark webbed feet. In winter, adult Common Loons appear similar to young birds, with dark gray heads and back contrasting with a white belly.
see a Common Loon in Algonquin Parkback to top
Weight: 2.7 to 6.3 kilograms. Loons are very heavy birds because of their solid bones which is unusual in the bird world
Migration: Common Loons live throughout Canada, from Newfoundland and Labrador to British Columbia, north to the Yukon, Northwest Territory and Nunavut. Common Loons can also be observed in the northeastern United States during the summer months. It is estimated that Ontario has about 65,000 pairs of Common Loons living in the province during the summer months. Near the end of summer, loons will gather on many of Algonquin's larger lakes prior to migration. Adults will usually migrate before young birds, which may need additional time to mature before migration. By the middle of November, most loons have left Algonquin Park for areas of open water to the south. Most loons migrate to the Atlantic Ocean, but a few may winter on the Great Lakes.
In the spring, loons gather on ice-free lakes to the south of Algonquin Park. On warm spring days, Common Loons can be observed flying north in search of ice free water bodies. In many situations, loons may then retreat south should they find ice covered lakes, or should cold wintry weather return. The first loons observed in Algonquin are usually near inlets and outlets of rivers where lake ice thaws first in mid-April. In many years, loons will occupy territories before all the ice has melted from many lakes.
Food Sources: Common Loons feed on fish such as Yellow Perch, Smallmouth Bass, and assorted smaller fishes usually referred to as "minnows". In addition, some loons feed on naturally fishless lakes, which contain crayfish, frogs, leeches and aquatic insects.
Loons hunt by swimming after their prey using their webbed feet. They have been known to dive to depths of 70 metres and stay submerged for more than three minutes, but the average dive is less than five metres deep and 40 to 45 seconds in duration.
Sounds: Common Loons are best known for their yodel, hoot, wail and tremolo calls heard by many Park visitors. However, the first sound that loons make is a 'peep-peep-peep' that is given by chicks when they are still inside the egg. Loons use their more commonly heard vocalizations for a variety of purposes. For example, the hoot call is used as a contact call as birds approach one another. The tremolo signals distress and may urge loons to move to safety. The yodel is used in territorial disputes, essentially stating to any loons close by - "This is our territory!" Finally, the wail indicates a willingness to interact and is used to reestablish contact between individuals when they have been separated.
Major Predators: Adult Common Loons have few predators. In Algonquin Park, Ospreys have been observed harassing adult and young birds. In addition, Bald Eagles have attacked loons while on the water.
Breeding: Common Loons arrive in Algonquin Park, as lake ice is melting, during mid to late April. Loons quickly begin to establish and defend breeding territories. Nests are built in May and June, and take about a week to complete. A nest is a pile of aquatic vegetation close to the edge of the water body, usually near a sheltered bay, island, point, or adjacent river system. Two olive-brown coloured eggs are laid in the month of June and are incubated for 28 days before hatching. While still small, young loons travel on the backs of their parents, as they do not have the stamina to keep up with them. This behaviour can be observed on many Park lakes during July and early August. By eight weeks of age young loons are fully feathered and can search for food independently of their parents. Young loons usually migrate later than adults in their first fall.back to top
Research Habitat: back to top
Common Loons utilize lakes and rivers in Algonquin Park to nest, sleep, and feed.
Learn more about Algonquin's lakes and rivers.
Is acid rain affecting Common Loons in Algonquin Park?
With the help of visitors and staff, Ron Tozer has been able to gather detailed loon observations since 1981. Summer visitors to the Park are encouraged to record their sightings at various locations, like the Algonquin Visitor Centre, East and West Gates, and Access Points. The number of adult loons, active loon nests, and young observed are recorded. By doing this, Ron is able to conduct a long-term study of Common Loons and their reproductive success on Algonquin Park lakes, in order to monitor trends in the population over time. Ron Tozer believes that "our loon population can serve as an indicator of the general health and condition of the Park's lakes, and may show results of impacts like acid rain." Since 1981, when the Loon Survey began, an average of 250 lakes have been surveyed each year. Active nests and/or young have been observed on approximately 30 to 50% of studied lakes. Ron suspects these results are "normal" for this population. However, monitoring of Algonquin Park loons will continue to watch for any future changes which might occur.
View a page of loon sightings from a recent Loon Survey year
Are Common Loons returning to Algonquin Park sooner than they used to?
In the 1970's the average spring arrival date for Common Loons in Algonquin Park was April 23. In the 1990s the average spring arrival date for Common Loons was April 16. This means that Common Loons are arriving in Algonquin Park on average one week earlier today, than they did just 40 years ago.
In early spring, Common Loons will conduct short forays into Algonquin Park to determine if conditions are suitable for their survival. Common Loons are regularly observed on mild early spring days flying high overhead to investigate the amount of open water present in Algonquin Park. If the spring is warm and conditions ice-free in some areas, loons will remain in these areas of open water to feed and begin to establish breeding territories. If conditions are unsuitable the loon retreats to warmer, open water areas farther to the south.
View a page from Ron Tozer's journal
Are other bird species returning to Algonquin Park sooner than they used to?
Ron Tozer has documented spring arrival dates for many other species in addition to Common Loons. Most of these observed species are also arriving earlier in Algonquin Park now than a few decades ago. For example, the average arrival for Great Blue Herons in Algonquin in the 1970s was April 4. In the 1990s, this species was returning on March 30. American Black Ducks are also arriving substantially earlier. In the 1970s the average arrival in the Park was April 8. In the 1990s, the date had increased to March 29.
Ron Tozer believes that long distance migrants, that spend the winter in places like Central and South America, are less affected by warming spring time temperatures since their migration is cued more by daylight length than temperature. For example, a Swainson's Thrush wintering in northern South America is not capable of determining how warm it is in Algonquin since it is thousand of kilometres away. Therefore, instinct (cued by daylight length) tells the bird to migrate, about the same time, each spring no matter the conditions in Algonquin Park. This is observed in the average spring arrival dates Ron Tozer has recorded for this species. In the 1970s, the average arrival date for Swainson's Thrush was May 20 and in the 1990s the average arrival date was virtually unchanged at May 19. Another example of this trend is the arrival dates for the American Redstart which spends the winter in Central America. Its average arrival date in the 1970s and the 1990s was May 12.
Are bird staying in Algonquin Park later into the fall than they used to?
If many species of birds are arriving in Algonquin Park earlier than in the past, one would also suspect that birds like Common Loons may be staying longer into the fall than they used to. "Fall departure dates are more difficult to determine than spring arrival dates" says Ron Tozer. "For example, in the spring, the first areas to melt are usually areas where rivers and creeks flow in or out of major water bodies. These locations where open water first appears are easy to predict, and thus, it is easier to determine the arrival date of the first aquatic birds, like loons, since there is less territory to search." However in the fall small, shallow, water bodies freeze first. Deeper water bodies like the Park's largest lake, Lake Opeongo, are often the last to freeze. Accurate fall observations are more difficult to obtain since observers often can not make it to the last little bit of open water, which would concentrate birds like loons, as a result of ice on shallower areas of lakes." As a result, Ron Tozer has less faith in his fall departure dates for bird species than the results he has for spring arrival dates. Despite this limitation, Ron suspects "that birds like Common Loons are likely staying much later than they did just 40 years ago, because of milder early winter conditions that result in open water later."
Why are birds arriving in Algonquin sooner and staying later in the autumn?
"Algonquin Park is not an island; it is not isolated from the outside world by the Park's boundaries. In fact, many problems like acid rain that begin well outside the boundaries of Algonquin Park can, and do, travel long distances and affect Algonquin Park" says Ron Tozer. One of these problems that is present in Algonquin is the concern over global climate change. Ron Tozer who was originally interested in the impacts of acid rain upon Algonquin' lakes and loons, may soon be able to reveal the implications of global climate change on bird species in the Park. With temperatures increasing, many bird species are now able to survive in Algonquin earlier in the spring. For example, with Common Loons, warmer spring temperatures, result in lakes thawing sooner, resulting in open water in which loons can feed and establish nesting territories earlier. Climate data shows that autumns are warmer too, resulting in later ice formation and providing suitable feeding locations for loons longer into the autumn. No one knows exactly what impacts climate change in Algonquin Park is having on the Common Loon, but Ron Tozer with his years of data on bird migration, loon populations, and loon nesting success, is in a very good position to learn more about the impacts of climate change in the future years of Common Loon research in Algonquin Park.
Educators: Learn more about Algonquin’s habitats, download readings and worksheets from the Educator Resources section of the Web Site, or you may also learn more through the following publications:
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