Trophic ecology of Yellow-billed Loons (Gavia adamsii) and Common Loons (G. immer) during the non-breeding season
DOI:
https://doi.org/10.15845/on.v49.4573Keywords:
diet , diving behaviour , food competition, gastroliths, winter ecologyAbstract
Cover photo: Common Loon Gavia immer with prey. Photo: Torborg Berge.
Diet and aspects of feeding behaviour of Yellow-billed Loons Gavia adamsii and Common Loons G. immer were compared during the non-breeding season in coastal Norway. Stomach contents from 14 Common Loons and 13 Yellow-billed Loons showed that fishes constituted the main prey of both species. However, saithe Pollachius virens constituted a major component of the diet of the Yellow-billed Loon, whereas wrasses (Labridae), flatfish (Pleuronectidae), and sandeel Ammodytes tobianus were important prey for Common Loons. Common Loons also frequently included crustaceans and sometimes molluscs in their diet. We tested the hypothesis that the Yellow-billed Loon, with its more upturned bill, feed more on bottom-living prey than the Common Loon. Contrary to the hypothesis, stomach contents indicated that more bottom-living prey were taken by Common Loons, and Yellow-billed Loons seemed to prey more on pelagic fish. A difference in prey selection was consistent with field observations that Yellow-billed Loons often fed in water judged too deep for bottom-feeding, social groups were often synchronized when feeding, and their stomach contents contained only a few gastroliths compared to Common Loons. Species differences in number of gastroliths indicate that Yellow-billed Loons are feeding on softer food such as pelagic fish, whereas Common Loons are feeding on crustaceans and the more armoured and spiny fishes occurring in bottom habitats.
References
Bailey AM. 1922. Notes on the Yellow-billed Loon. Condor 24: 204–205.
Barr JF. 1996. Aspects of Common Loon (Gavia immer) feeding biology on its breeding ground. Hydrobiologia 321: 119–144.
Blacker RW. 1983. Pelagic records of the lumpsucker, Cyclopterus lumpus L. Journal of Fish Biology 23: 405–417.
Breiby A. 1985. Otolitter fra saltvannsfisk i Nord-Norge. Tromura 45: 1–31.
Brinkmann A Jr. 1949. Sigurd Johnsen, 25. desember 1884–29. august 1949. Naturen 73: 193–196. (In Norwegian)
Byrkjedal I, Breistøl A, Mjøs AT & Strann K-B. 2000. Winter habitat of White-billed and Great Northern Divers (Gavia adamsii and G. immer) on the coast of Norway. Ornis Norvegica 23: 50–55.
Byrkjedal I. 2011. Social behaviour of wintering Great Northern Divers Gavia immer in relation to age categories. Ornis Norvegica 34: 10–16.
Byrkjedal I. 2017. Interspecific aggression by wintering Great Northern Divers Gavia immer. Ornis Norvegica 40: 49–54. doi: 10.15845/on.v40i0.1379
Collett R. 1894a. Mindre meddelelser vedrørende Norges fuglefauna i aarene 1881–1892. Nyt Magazin for Naturvidenskaberne 35: 323. (In Norwegian)
Collett R. 1894b. On the occurrence of Colymbus adamsi in Norway. Ibis 6: 269–283.
Cottham C & Knappen P. 1939. Food of some uncommon North American birds. Auk 56: 138–169.
Cramp S & Simmons KEL. (eds.) 1977. The birds of the Western Palearctic, Vol. 1. Oxford University Press, Oxford, UK.
Daub BC. 1989. Behavior of Common Loons in winter. Journal of Field Ornithology 60: 305–311.
Eriksen E, Durif CMF & Prozorkevich D. 2014. Lumpfish (Cyclopterus lumpus) in the Barents Sea: development of biomass and abundance indices, and spatial distribution. ICES Journal of Marine Science 71: 2398–2402. doi: 10.1093/icesjms/fsu059
Evers DC, Paruk JD, Mcintyre JW & Barr JF. 2010. Common Loon (Gavia immer). In Poole A (ed.) The Birds of North America Online. Cornell Lab of Ornithology, Ithaca NY, USA. Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/313
Folvik A & Mjøs AT. 1995. Spring migration of White-billed Divers past southwestern Norway. British Birds 88: 125-129.
Ford TB & Gieg JA. 1995. Winter behavior of the Common Loon. Journal of Field Ornithology 66: 22–29.
Friedrich H. 1969. Marine biology: an introduction to its problems and results. Sidgwick & Jackson, London, UK.
Guðmundsson F. 1952. Íslenskir fuglar I: Himbrimi (Colymbus immer Brünn.) Náttúrufræðingurinn 22: 44–45. (In Icelandic)
Haney JC. 1990. Winter habitat of Common Loons on the continental shelf of the southeastern United States. Wilson Bulletin 102: 253–263.
Heubeck M, Richardson MG, Lyster IHJ & McGowan RY. 1993. Post mortem examination of Great Northern Divers Gavia immer killed by oil pollution in Shetland, 1979. Seabird 15: 53–59.
Holst JC. 1993. Observation on the distribution of lumpsucker (Cyclopterus lumpus, L.) in the Norwegian Sea. Fisheries Research 17: 369–372.
Il’ičev VD & Flint VE. 1982. Handbuch der Vögel der Sowjetunion. Vol. 1. A. Ziemsen Verlag, Wittenberg Lutherstadt, Germany.
Jonsson L & Tysse T. 1992. Lommar. Vår Fågelvärld, Suppl. 15. (In Swedish)
Jehl JR. 1970. A Mexican specimen of the Yellow-billed Loon. Condor 72: 376.
Leopold MF, van Leeuwen PW, Horn H & Camphuysen K. 2000. Grote Ijsduiker Gavia immer eet kleine visjes: een verdronken vogel geeft geheimen prijs. Limosa 73: 135–143.
Madsen FJ. 1957. On the food habits of some fish-eating birds in Denmark. Danish Review of Game Biology 3: 19–83.
McIntyre JW. 1988. The Common Loon: spirit of the northern lakes. University of Minnesota Press, Minneapolis MN, USA.
McIntyre JW & Barr JF. 1997. Common Loon Gavia immer. In Poole A & Gill F (eds.) The Birds of North America, No. 313. The Academy of Natural Sciences, Philadelphia PA and The American Ornithologists’ Union, Washington DC, USA.
Mecklenburg CW, Lynghammar A, Johannesen E, Byrkjedal I, Christiansen JS, Dolgov A, Karamushko V, Mecklenburg TA, Møller PR, Steinke D & Wienerroither RM. 2018. Marine fishes of the Arctic Region. CAFF, Akureyri, Iceland. http://hdl.handle.net/11374/2116
Moen FE & Svensen E. 2000. Dyreliv i havet – håndbok i norsk marin fauna. Komi forlag, Kristiansund, Norway. (In Norwegian)
Muus BJ & Nielsen JG. 1998. Våre saltvannsfisker. NKS-forlaget, Oslo, Norway. (In Norwegian)
North MR. 1994. Yellow-billed Loon Gavia adamsii. In Poole A & Gill E (eds.). The birds of North America, No. 121. The Academy of Natural Sciences & The American Ornithologists’ Union, Philadelphia PA & Washington DC, USA.
Paruk JD, Evers DC, McIntyre JW, Barr JF, Mager J & Piper WH. 2021. Common Loon (Gavia immer), version 2.0. In Rodewald PG & Keeney BK (eds). Birds of the World. Cornell Lab of Ornithology, Ithaca NY, USA. https://birdsoftheworld.org/bow/species/comloo/cur/introduction
Paulson DR. 1988. An incident of Common Loons eating clams. The Murrelet 69: 53–54.
Pethon P. 2019. Aschehougs store fiskebok. Aschehoug, Oslo, Norway. (In Norwegian)
Portenko LA. 1981. Birds of the Chukchi Peninsula and Wrangel Island, Vol. 1. Amerind Publ., New Delhi, India. (English translation of Portenko, LA. 1972. Ptitsy Chutotskogo poluostrova i ostrova Vrangelya. Nauka, Leningrad, USSR)
Reay PJ. 1986. Ammodytidae. Pp. 945–950 in Whitehead PJP, Bauchot M-L, Hureau J-C, Nielsen J & Tortonese E (eds.). Fishes of the north-eastern Atlantic and the Mediterranean. Vol. 2. Unesco, Paris, France.
Schorger AW. 1947. The deep diving of the Loon and Old Squaw and its mechanism. Wilson Bulletin 59: 151–159.
Storer RW. 1978. Systematic notes on the loons (Gavidae: Aves). Breviora Museum of Comparative Zoology. No. 448.
Uher-Koch BD, North MR & Schmutz JA. 2020. Yellow-billed Loon (Gavia adamsii), version 1.0. In Billerman, SM (ed.). Birds of the World. Cornell Lab of Ornithology, Ithaca NY, USA. https://birdsoftheworld.org/bow/species/yebloo/cur/introduction
Whitehead PJP, Bauchot M-L, Hureau J-C, Nielsen J & Tortonese E (eds.). 1984–1986. Fishes of the north-eastern Atlantic and the Mediterranean. Unesco, Paris, France.
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2026 Ingvar Byrkjedal, Olaug Flatnes Bratbak, Terje Lislevand
This work is licensed under a Creative Commons Attribution 4.0 International License.
Articles published prior to September 2020 are subject to the following terms: https://boap.uib.no/index.php/ornis/copyright
