Arctic Loon Similar Species Comparison
Main SpeciesArctic Loon
Breeding adult
A medium-sized loon with a thick neck and straight bill. Breeding adult has a pale gray crown and hindneck, black-and-white stripes on the side of the neck, a dark chin and throat, very fine black lines on the breast, and prominent white marks on dark upperparts. Note the prominent white flank patch just above the waterline.
© Ian Davies / Macaulay LibrarySouthern Savonia, June 07, 2015Nonbreeding adult
Note the white flank patch, which is the best way to identify vagrant individuals in North America.
© Brian Sullivan / Macaulay LibraryCalifornia, January 13, 2012Breeding adult
A medium-sized loon with intricate black, white, and gray breeding plumage. Birds across Europe and most of northern Asia have a deep purple throat in good light.
© Josep del Hoyo / Macaulay LibraryNorthern Ostrobothnia, May 07, 2016Nonbreeding adult
Nonbreeding adult has blackish upperparts and neck that contrast strongly with white throat and chin. Bill is mostly gray, with a dark line along the top and a black tip.
© Pavel Štěpánek / Macaulay LibraryJihomoravský kraj, December 07, 2017Immature
Juvenile is similar to nonbreeding adult, but paler and browner. At close range, upperparts appear scaly due to light feather edges.
© Ramit Singal / Macaulay LibraryBeijing, November 03, 2018Nonbreeding adult
Nonbreeding adult is mostly dark overall, with strongly contrasting white cheeks, throat, and flank patches.
© Brian Sullivan / Macaulay LibraryCalifornia, January 12, 2012Breeding adult
In good light, breeding adults in Europe and most of Asia show a purplish shine on the throat.
© Jonathan Farooqi / Macaulay LibraryScotlandBreeding adult
Flies strongly on long, narrow wings with neck outstretched and feet extended beyond body.
© James Kennerley / Macaulay LibraryJämtlands län [SE-23], June 09, 2017Breeding adult
Pairs nest along large freshwater lakes across the boreal forest of northern Europe and Asia.
© Josep del Hoyo / Macaulay LibrarySakha, June 29, 2019Immature
Juvenile is paler and browner than nonbreeding adult, with a duskier transition between the neck and throat.
© Pavel Štěpánek / Macaulay LibraryTrnavský kraj, October 19, 2019Molting adult
White flank patch is present in all plumages, but can be difficult to see depending on an individual’s posture.
© Roman Chaley / Macaulay LibraryMinskaja voblasc', October 23, 2020Juvenile
Juvenile is lighter colored and browner than nonbreeding adult, with a light scaly pattern on upperparts. The diagnostic white flank patch is mostly concealed while this individual is swimming, but is evident when it dives.
© Pedro Fernandes / Macaulay LibraryGrad Zagreb, November 28, 2022Breeding adult
Often gathers in small groups outside of the breeding season.
© ANASTASIYA SAMOKHINA / Macaulay LibraryMurmansk Oblast, September 08, 2020Similar SpeciesPacific Loon
Breeding adult
Breeding Pacific Loon has a paler gray nape than Arctic Loon, and thinner, more widely spaced white lines on the side of the neck. Pacific Loon often has a more rounded head than Arctic Loon (which often has a steep forehead and flat crown), but head shape in both species can vary depending on posture.
© Tyler Ficker / Macaulay LibraryAlaska, June 14, 2019Similar SpeciesPacific Loon
Nonbreeding adult
Pacific Loon is somewhat smaller than Arctic Loon, with a slightly smaller bill, and it typically has a thin chinstrap across the throat in nonbreeding plumage. The best way to differentiate nonbreeding Pacific Loon from Arctic Loon, though, is the presence of a white flank patch in Arctic Loon and the absence of such a patch in Pacific Loon.
© Daniel Irons / Macaulay LibraryMaryland, April 09, 2019Similar SpeciesPacific Loon
Juvenile
Juvenile Pacific Loon lacks the white flank patch found on juvenile Arctic Loon.
© Nigel Voaden / Macaulay LibraryEngland, January 22, 2017Similar SpeciesRed-throated Loon
Nonbreeding adult
Red-throated Loon is smaller than Arctic Loon, with a more slender neck, and tends to hold its bill above the horizontal. Nonbreeding Red-throated Loon is paler than Arctic Loon, with more white on the face and neck and extensive white speckling on the upperparts.
© Dorian Anderson / Macaulay LibraryCalifornia, December 08, 2018Similar SpeciesCommon Loon
Breeding adult
Common Loon is larger than Arctic Loon, with a heavier bill. Breeding Common Loon has an all-black head and a horizontal collar of short white lines around the back of the neck.
© Christian Hagenlocher / Macaulay LibraryVermont, June 23, 2020Similar SpeciesCommon Loon
Nonbreeding adult/immature
Nonbreeding Common Loon lacks the white flank patch found on Arctic Loon, and shows a dark partial collar on the neck (as opposed to the clean dark/light vertical line on Arctic Loon).
© Marky Mutchler / Macaulay LibraryMissouri, November 10, 2020Compare with Similar Species
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