Common Loon (Gavia immer)

Loon with multi-colored plumage, brown head, and bright red eyes floating in a pond
An adult common loon in breeding plumage.
Category: Birds
State status: Sensitive
Vulnerability to climate change (More details)


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The common loon has a small breeding population in Washington. Its overall range has contracted northward. Due to life history and a small population in Washington it is highly vulnerable to impacts if not monitored and managed where appropriate. Increased development and recreational pressure at sensitive nesting lakes must be actively managed to prevent further loss of nesting loons.

Description and Range

Physical description

Common loons typically measure 26 to 36 inches, with a 50 to 55-inch wingspan. They weigh 8.4 to 19 pounds. Males are larger than females and territorial individuals tend to be larger than those not on territories. Both male and female common loons bear black and white plumage during the breeding season. In winter, loons acquire a gray above, white below basic plumage. Subadult loons may remain in basic plumage year-round.

Ecology and life history 

Close up of a  pair male and female loons in breeding plumage facing each other on the water
Male and female common loons in breeding plumage. Gary J. Wege - USFWS Midwest Region

In winter and during migration, common loons use inland lakes and rivers and marine and estuarine coastal waters.

Common loons feed mainly on fish, typically of a size between 0.35 to 2.45 ounces. In fresh water, these include shad, alewife, trout, smelt, mudminnows, dace, chubs, shiners, suckers, sticklebacks, bluegills, crappie, yellow perch, and walleye. Saltwater prey include eels, menhaden, herring, sprat, haddock, whiting, pipefish, shiner perch, sandlance, gobies, blennies, Irish lords, gurnards, sculpins, flounder, sole, and skates. They also occasionally take amphibians, crayfish, small crabs, and dragonflies; and in eastern Washington, adults have been observed feeding dragonfly nymphs to their chicks.

Breeding habitat includes usually clear lakes containing both shallow and deep-water areas. Nest sites are on small islands, quiet backwaters, or mainland shores. Loons have been found nesting in marshy portions of lakes in water depths no greater than 1.6 feet. Nests are built at the water's edge and egg-laying generally begins between mid-May and mid-July. Optimal nest sites include overhead cover to conceal eggs from predators, protection from wind and waves, good visibility by incubating adults, and a steep slope adjacent to the nest for adequate underwater approaches and exits.

Brood-rearing areas are typically located in shallow coves of fairly uniform depth, sheltered from prevailing winds and wave action, and are independent of nest site location. Chicks leave the nest within 24 hours of hatching and are soon moved to nursery areas. Chicks may be carried on their parents' backs until they reach three weeks of age. Most juveniles are capable of flight at 11 to 12 weeks, and some leave their small, natal lakes or parental territories shortly afterward.

Non-breeders aggregate in marine waters, but also inland freshwater bodies.

Geographic range

Common loons breed in freshwater habitats of northern North America including much of Canada, Alaska, northern portions of the contiguous United States, and southern Greenland. They also breeds in Iceland. The southern portion of their historical breeding range has contracted. These birds spend winters on inland larger freshwater bodies and marine environments from Alaska to northern Mexico in the American west.

Common loons once were described as a fairly common breeding species both east and west of the Cascade crest, but likely declined between 1890 and 1925 in much of Washington. Declines across the United States during this period are thought to have been the result of shooting.

In Washington, breeding areas are freshwater lakes and reservoirs, mainly in remote areas of northeastern and northwestern parts of the state. Common loons spend the winter in almost all nearshore marine and larger freshwater bodies of western Washington. They are uncommon and irregular in winter in eastern Washington where they are found in large water bodies and Columbia Basin impoundments. The size of Washington’s breeding population is unknown.

For a map reflecting this species' conservation status and other species' information, check out NatureServe Explorer and the International Union for Conservation of Nature Redlist.  

Climate vulnerability

Sensitivity to climate change


Though limited information is available regarding the sensitivity of common loons to climate change, they may experience some direct sensitivity to climate change through northward contractions of their range with increasing temperatures and altered migration timing. Their sensitivity may be increased by changes to their prey and habitat. For instance, Pacific herring, a primary food source for loons, have previously experienced declines during El Niño years, leading to high mortality for loons; more frequent and stronger El Niño conditions could lead to greatly decreased food supply for loons.

Confidence: Moderate

Exposure to climate change


  • Increased temperatures (air and ocean)
  • Altered global climate patterns (i.e., El Niño)
Confidence: Low


Rules and Seasons

Managing use of lead fishing tackle

Ingestion of small lead fishing tackle is the leading cause of known mortalities of the common loon, a sensitive species in Washington that is likely to become threatened or endangered without improved survival.

Managing the use of lead fishing tackle at the 13 lakes in Washington where loons breed and rear young is intended to improve loon survival by keeping loons from being poisoned by ingesting small lead fishing gear lost by anglers.

Restrictions on lead usage at those lakes were adopted by the Fish and Wildlife Commission in December 2010 and went into effect on May 1, 2011.

These rules prohibit the use of lead weights and jigs that measure an inch and a half or less along the longest axis at 12 lakes:

  • Ferry and Swan lakes in Ferry County
  • Calligan and Hancock lakes in King County
  • Bonaparte, Blue, and Lost lakes in Okanogan County
  • Big Meadow, South Skookum, and Yocum lakes in Pend Oreille County
  • Pierre Lake in Stevens County
  • Hozomeen Lake in Whatcom County

In addition, the commission banned the use of flies containing lead at Long Lake in Ferry County.

Information on lead-free alternatives, including manufacturers and retailers, is provided by LoonWatch.


This species is identified as a Species of Greatest Conservation Need (SGCN) under the State Wildlife Action Plan (SWAP). SGCN-classified species include both those with and without legal protection status under the Federal or State Endangered Species programs, as well as game species with low populations. The WDFW SWAP is part of a nationwide effort by all 50 states and five U.S. territories to develop conservation action plans for fish, wildlife and their natural habitats—identifying opportunities for species' recovery before they are imperiled and more limited.
This species is identified as a Priority Species under WDFW's Priority Habitat and Species Program. Priority species require protective measures for their survival due to their population status, sensitivity to habitat alteration, and/or recreational, commercial, or tribal importance. The PHS program is the agency's main means of sharing fish and wildlife information with local governments, landowners, and others who use it to protect priority habitats for land use planning.

Conservation Threats and Actions Needed

  • Fish and wildlife habitat loss or degradation
    • Threat: Shoreline and adjacent upland development, use and degradation by various land use change actions (such as development, timber harvest, stormwater runoff impacts, increase pollutant exposure).
    • Action: Work with private and public landowners to support and sustain habitat and support healthy ecosystem processes.
    • Threat: Human consumptive and non-consumptive recreational intrusion on breeding lakes; lead tackle impacts; direct disturbance of nesting and brooding by recreation activities.
    • Action: Provide outreach to educated constituents regarding curbing recreation impacts.
  • Outreach needs
    • Threat: Lead tackle use, gear entanglement, oil spill, commercial fish bycatch impacts require more outreach and management attention
    • Action:  Provide outreach to educate constituents regarding curbing recreation impacts.
  • Coordination – administration needs
    • Threat: Maintain and increase collaboration with landowners and constituents to manage hydroelectric sites used for breeding by providing platforms.
    • Action: Emphasize need for platforms on managed waters that have flux and resident loons.

See the Climate vulnerability section above for information about the threats posed by climate change to this species. In addition, the use of rotenone to kill unwanted fish may affect the food supply of common loons for several years.

See the Regulations section above for information about managing the use of lead fishing tackle. 


WDFW Publications

Status report

Fact sheet