Red-throated Loon: At Risk

Red-throated loons are very widespread and are not threatened worldwide, but some populations are declining and are at risk.  Factors contributing to the decline of this species include habitat degradation and loss, fishing lines, oil spills, and offshore wind turbines.  Loons, like other aquatic birds, are also negatively impacted by high levels of mercury in the environment.  These factors, combined with the natural predation on loons and their eggs by foxes and gulls, have led to declines in some populations, particularly in Alaska.

Red-throat wrapped in fishing line.

While red-throated loons are not at risk of extinction right now, it may be beneficial to protect and conserve the species with habitat enhancement and restoration.  This species is protected under the Migratory Bird Treaty Act of 1918.

Loon Reproduction

The five species of loons are fairly similar in their breeding tendencies.  Common loons, as an example, nest on lakes and ponds and have an elaborate courtship process involving preening, head dipping, soft calling, displaying of the white neck, and swimming in circles with prospective mates.  Males choose the location of the nests, which are constructed very close to the water by both males and females.  Contrary to popular belief, loons are not monogamous.  Territory takeover and extra-pair copulation are fairly common.  Most clutches consist of two eggs, and chicks are precocial, able to swim and dive immediately after hatching.  Chicks may also ride on their parents’ back for a time to conserve heat and energy.

Common loon and chicks.

Other species of loons follow this basic reproduction procedure.  Red-throated loons vary slightly in that both males AND females vocalize.  Red-throated chicks also do not ride on their parents’ backs.

Red-throated loon pair.

The Call of the Loon

The call of the common loon is one of the most well-known and comforting sounds heard on lakes from upstate New York and into Canada.  They give a rising 2-note wail, sometimes topping it off with a higher 3rd note.  The call is very haunting, and sometimes sounds like wolves howling.  A good example of multiple individuals wailing can be found here.

Another common type of call is the "laughing call", which is actually the alarm call of the birds. It is also sometime used in territory defense.  This call is a series of quick rising rising and falling notes that actually sounds a bit like laughter.  This call, and other loon calls, can be heard here.

Morphological Characteristics

Loons, also called “divers,” have distinctive breeding and winter plumages, which can make identification difficult.  They have small wings (and thus high wing loading), short legs, and heavy bodies with webbed feet that are set back.  They have pointed bills that are used to catch fish while diving.  Summer plumages are brightly colored and patterned, and loons swim very low in the water.   Males and females have identical plumages, but males are larger on average

Loons were classified in the same order as grebes (collectively known as Colymbiformes) until the 1930s, when it was determined that morphological similarities were due to convergent evolution instead of common ancestry.  Grebes were moved to Podicipediformes, while loons went to Gaviiformes.

Common loon in flight.

Red-throated loon swimming low in the water.

Common loon diving.

Webbed foot of common loon.

Baby common loon on mother's back.

Sources:

• Alderfer, Jonathan.  2006. Complete Birds of North America, pp. 58-61. National Geographic, Washington, D.C.
• Peterson, Roger Tory.  2010. Peterson Field Guide to Birds of Eastern and Central North America, 6^th Edition, pp. 58-59. Houghton Mifflin Harcourt, Boston and New York.  

Loons

The loons are a group of 5 species of birds representing only one genus (Gavia) and one family (Gaviidae).  Two species, the common loon and the red-throated loon, occur in eastern North America.  Loons are large aquatic birds with long bodies for diving.  They have sharp bills and long webbed feet that extend beyond their short tail.  Their bellies are submerged when swimming and they appear plump when flying.  They are clumsy when walking on land and only come ashore to nest.

Loons are seasonally monogamous.  Pair bonding displays include synchronous dives and circular swimming.  Males choose the location of the nests, which are generally built in protected areas near water, such as an island or in emergent vegetation.  Males defend territories by “yodeling.”  Other types of calls include peeps, yelps, hoots, and wails.

Four out of the 5 species of loon are considered by the IUCN to be of “least concern.”  The fifth species, the yellow-billed loon, is “near-threatened,” the main threat being over-harvesting by indigenous peoples in the Arctic.

Pacific loon

Yellow-billed loon

Black-throated loon

Red-throated loon

Common (or great northern) loon
 

Sources:

• Alderfer, Jonathan.  2006. Complete Birds of North America, pp. 58-61. National Geographic, Washington, D.C.
• All About Birds. 2011. “Loons.” http://www.allaboutbirds.org/guide/browse_tax/28/. Cornell Lab of Ornithology.  Accessed June 1, 2012.
• The Birds of North America Online. 2012 “Common Loon.” http://bna.birds.cornell.edu/bna/species/313/articles/introduction. Cornell Lab of Ornithology.  Accessed June 1, 2012.
• National Audubon Society. 2000. Field Guide to Birds (Eastern Region), pp. 337-339. Random House, New York.
• Peterson, Roger Tory.  2010. Peterson Field Guide to Birds of Eastern and Central North America, 6^th Edition, pp. 58-59. Houghton Mifflin Harcourt, Boston and New York.