Reproduction edit
During the summer, loons build their nests on large ponds or freshwater lakes. Smaller bodies of water (up to 0. 5 km2) will usually only have one pair. Larger lakes may contain multiple pairs, each of which may occupy a bay or other area of the lake. On the other hand, the red-throated loon can breed in small Arctic tarns in colonies, with multiple pairs nesting close to each other. It can also feed at larger lakes or the ocean, bringing food in for its young. [7][8].
Loons construct their nests near bodies of water, preferably on sites that are entirely encircled by water, like islands or emergent vegetation. They mate on land, frequently on the potential nest site. To construct their nests, loons use a range of materials, such as mud, aquatic vegetation, pine needles, leaves, grass, and moss. Sometimes, nest material is almost lacking. The male and female work together to construct the nest and incubate it for 28 days. The pair may re-nest if the eggs are lost; typically, they will do so in a different place. Given the nest’s proximity to the water, rising water levels may cause the birds to gradually raise the nest by more than a meter. [7][8].
- Common loon on the nest
- Juvenile red-throated loon
- Common loon feeding its young
- Immature common loon with crayfish
Even though both sexes contribute roughly equally to nest construction and incubation, analysis has made it abundantly evident that only males choose the nest’s location. Male loons, but not females, develop a strong site-familiarity with their territories, which enables them to raise more chicks there over time. This pattern has an important consequence. Part of the reason why resident males fight so hard to defend their territories may be due to sex-biased site familiarity. [10].
Depending on the latitude, most clutches of two eggs are laid in May or June. In their first two weeks of life, loon chicks are precocial and can swim and dive immediately, but they also frequently spend this time riding on their parents’ backs to rest, store heat, and fend off predators. For roughly six weeks, chicks are primarily fed by their parents; however, over time, they gradually start to feed themselves. Chicks begin to fly at 11 or 12 weeks of age, and they are able to gather nearly all of their own food. [7][8] In 2019, a bald eagle discovered floating on a Maine lake had its necropsy, and it was discovered that the adult loon’s beak had stabbed the eagle through the heart. [11].
Researchers in biology, particularly those at Chapman University, have studied the common loon’s mating habits in great detail (G immer). Contrary to popular belief, pairs seldom mate for life. In fact, because of territorial takeover, an adult loon is likely to mate multiple times in its lifetime. Every breeding pair has to constantly defend their territory from adults without a territory who try to evict one or more of the owners and take over the breeding site. Given that nonbreeding loons use chicks as cues to identify high-quality territories, territories that have produced chicks within the last year are particularly vulnerable to takeovers. Male loons evict their owners in one-third of cases; female loons, on the other hand, typically survive. When displaced from their territory, birds typically attempt to re-establish a breeding territory later in life by re-mating. [12][13][14][15].
2020 saw the hatching of a loon in Southeastern Massachusetts at Fall River for the first time in more than a century, according to the Massachusetts Division of Fisheries and Wildlife and Biodiversity Research Institute. In 2015, the chicks were moved in an attempt to restore their nesting and breeding habits. [16].
Behaviour and ecology edit Loons swimming in Wood Lake, BC on a summer morning
Because they can swim well, loons can move both above and below the surface of the water with their feet. Loons can run short distances to reach water when they’re afraid, but they have trouble walking on land because their feet are far back on their bodies. Loons avoid landing as a result, with the exception of mating and nesting. [4].
Although their high wing loading (mass to wing area ratio) makes takeoff more difficult, loons are strong flyers. In fact, in order for most species to produce enough lift to take flight, they must run across the surface of the water upwind while flapping their wings. [5] Only the red-throated loon (G. stellata) can take off from land. Once airborne, loons are capable of long flights during migration. Scientists from the U. S. Geological Survey, who have given some people satellite transmitter implants, has observed daily flights of up to 1078 km over a 24-hour period. These flights are most likely the result of solitary movements. [6] Loons from North Europe migrate mostly via the South Baltic and then directly across land to the Mediterranean or Black Sea. Loons have a 30-year lifespan and can hold their breath underwater for up to 90 seconds. [7][8].
As migratory birds, loons migrate to southern marine coastlines during the winter from their nesting habitats in northern freshwater lakes. However, because they have unique salt glands right above their eyes, they are well adapted to this change in salinity. After a protracted migration, these glands allow them to instantly eat fish from the ocean and drink saltwater by filtering out the salts in their blood and flushing the salty solution out of their nasal passages. [9].
Etymology and taxonomy edit
The birds’ practice of swimming serenely along the surface and then suddenly diving into the water to catch fish gave rise to the European Anglophone name “diver.” The Old English word lumme, which means lummox or awkward person, or the Scandinavian word lum, which means lame or clumsy, are most likely the sources of the North American name “loon.” In any case, the name alludes to the loon’s inadequate land mobility. [17].
An additional potential source is the Norwegian term lom, which refers to these birds and is derived from Old Norse lómr, which may be related to the English word “lament” due to the distinctive whining sound made by loons. [18] The scientific name Gavia refers to seabirds in general. [19].
The scientific term for the smew (Mergellus albellus) was the Latin term Gavia. This little sea duck is just another black-and-white seabird that swims and dives for fish; it has nothing to do with loons. Since loons are restricted to higher latitudes and appear to have only occurred as uncommon winter migrants in the Mediterranean region since the end of the last glacial period, it is unlikely that the ancient Romans knew much about them. [20][21].
It took until the 18th century for the term “gavia” to be applied to loons instead of ducks. Before Carl Linnaeus published the first modern scientific description of a Gavia species in 1758, naturalists referred to the loons as mergus, the Latin term for diving seabirds of all kinds, or colymbus. Regretfully, there was a lot of misunderstanding regarding whether Linnaeus’ “wastebin genus” Colymbus referenced grebes or loons. While European ornithologists, such as Nicholas Aylward Vigors and Richard Bowdler Sharpe, used the genus name for loons, North American ornithologists used it to refer to grebes.
In an attempt to resolve the dispute, the International Commission on Zoological Nomenclature established Gavia, which Johann Reinhold Forster named for the loons in 1788, as the legitimate genus name for loons in 1956 and declared Colymbus to be a suppressed name unfit for use going forward. Even so, the issue was not entirely settled, and the ICZN had to take further action the following year to stop Louis Pierre Vieillot’s 1818 nearly-forgotten family name Urinatoridae from superseding the far younger Gaviidae. Although some renowned ornithologists, like Pierce Brodkorb, attempted to prolong the discussion, the ICZN’s solution has proven to be adequate. [21][22][23][24].
FAQ
Are loons a type of duck?
What type of animal is a loon?
What bird is known as the loon?
Is the loon a state bird?