Gavia immer

Common loons primarily eat fish, but they also eat other small animals. When they nest on lakes that do not have fish, adult loons often feed their young with insects and other invertebrates, but fly to other lakes to find fish to eat themselves.
 
Photo Credit: Geoffrey A. Hammerson
Gavia immer
Common Name: common loon
Other Common Names: great northern diver
Animal Guild: Bird
Class > Order > Family: Aves > Gaviiformes > Gaviidae
What does the species look like?

Common loons are large-bodied, elongate birds with a heavy bill. Breeding adults have a black head and bill and white checkering on the back. Juveniles and winter adults are rather plain gray on the upper side and white below, with an irregular edge where the gray and white meet on the side of the neck. The wingspan is around 46 inches (117 cm).
 
Where is the species found?
States & Provinces
AB, AK, AL, AR, AZ, BC, CA, CO, CT, DE, FL, GA, ID, KS, KY, LA, MA, MB, MD, ME, MI, MN, MO, MS, MT, NB, NC, ND, NE, NH, NJ, NL, NM, NS, NT, NU, NV, NY, OH, OK, ON, OR, PA, PE, QC, RI, SC, SD, SK, TN, TX, UT, VA, VT, WA, WI, WV, WY, YT
Distribution

Nesting occurs in Iceland, Greenland, and across Canada and the northern United States to Alaska, and south to California, Montana, the Great Lakes region, New York, New England, and Nova Scotia. In winter, this loon occurs mainly along the Pacific coast from the Aleutians to Baja California and Sonora, along the Atlantic and Gulf coasts from Newfoundland to Florida and west to Texas, and in the western Palearctic along the Atlantic coast to northwestern Africa.
 

Breeding habitat includes clear lakes containing both shallow and deep water areas. Common loons nest on small islands or mainland shores. They typically raise their young in shallow coves. In winter and during migration, they  can be found on inland lakes and rivers, and marine and estuarine coastal waters.
 
General Phenology and Life History

Northward migration occurs mainly in April and May. The southward return begins late August and early September in the interior of the country, and continues until freeze-up. Migrants arrive in the far north (northern Alaska) in late May or early June. In the southern part of the nesting range, they may arrive as early as March. They lay eggs one to several weeks after arriving at their breeding grounds in the spring, usually during mid-May in the south, and well into June farther north. If the first clutch fails, they may lay new eggs (a replacement clutch) as late as early July. They incubate eggs for around four weeks. Chicks leave the nest within 24 hours of hatching and are soon moved to nursery areas. Adults may carry chicks on their backs until the chicks reach three weeks of age. Most juveniles are capable of flight at 11 to 12 weeks, and some leave the lakes where they were born shortly afterward.
 
Which phenophases should I observe?
Do you see/hear...?
Activity Live individuals
One or more individuals are seen or heard moving about or at rest.
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Feeding
One or more individuals are seen feeding or foraging. If possible, record the name of the species or substance being eaten or describe it in the comments field.

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Calls or song
One or more individuals are heard calling or singing.

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Territorial individuals
One or more individuals are seen or heard defending a territory. This may be indicated by calls or song used as part of a territorial proclamation, chasing of an individual of the same species from a breeding area (but do not confuse this with courtship behavior, which in some species may involve chasing), or calls or displays directed at individuals of the same or a different species to defend a feeding area.

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Reproduction Courtship
A male and female are seen near one another and are engaged in courtship behavior. Do not include male displays in the absence of a female.

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Mating
A male and female are seen coupled in a mating position, usually with the male on top of the female.

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Nest building
One or more adults are seen constructing a nest or carrying nesting material.

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Occupied nest
One or more adults are seen sitting on a nest, entering or leaving a nest site under circumstances indicating its use for nesting (including nest defense behavior), or live eggs or nestlings are seen in a nest.

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Development Downy young
One or more young are seen covered with fluffy down feathers and not yet any smooth contour feathers.

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Partially-fledged young
One or more young are seen with a mix of fluffy down and smooth contour feathers, and often have an unkempt or ragged appearance.

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Fledged young
One or more young are seen covered with smooth contour feathers and no longer any fluffy, natal down feathers. This includes young incapable of sustained flight and young which are still dependent on adults.

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Dead individuals
One or more dead individuals are seen.

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Dead nestlings or fledglings
One ore more dead nestlings or young are seen.

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Method Individuals at a feeding station
One or more individuals are seen visiting a feeder, feeding station, or food placed by a person.

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What do these phenophases look like?

There is currently no photoguide available for this species. If you'd like help us create one, use the guidance document and species template provided here. Then send it via email to education@usanpn.org when it is complete.