Common loons

Water birds have not been shown to be directly affected by acidification. However, the prey of waterbirds may be of concern as these lower food-chain organisms may have elevated levels of toxic metals related to acidification of their habitat. Moreover, most water birds rely on some component of the aquatic food-chain for their high protein diet. Invertebrates that normally supply caJcium to egg-laying birds or their growing chicks are among the first to disappear as lakes acidify. As these food sources are reduced or eliminated due to acidification, bird habitat is reduced and reproductive rate of the birds is affected. The Common Loon is able to raise fewer chicks, or none at all, on acidic lakes where fish populations are reduced 37 and 5S). However, in some isolated cases, food supplies can be increased when competitive species are eliminated (e.g.. Common Goldeneye ducks can better exploit insects as food when competition from fish is eliminated). The collective influences of acidification are difficult to quantify on a specific area basis but for species that rely on a healthy aquatic ecosystem to breed, acidification remains a continuing threat in thousands of lakes across eastern North America 14). 

Wayland, M. McNicol, D.K. Status Report on Effects of Acid Precipitation on Common Loon Reproduction in Ontario The Ontario Loon Survey, Can. Wildlife Serv., Tech. Rept. Ser., No. 92, Ottawa, Ontario, 1990. 

In a study conducted during the period 1998-2000 at North American sites, the relationship was studied between methyl mercury blood levels in common loons and behavioral parameters (Evers et al. 2008). Adult behaviors were divided into two... 

Burgess, N.M. and Meyer, M.W. (2008). Methyl mercury exposure associated with reduced productivity in common loons. Ecotoxicology 17, 83-92. 

Evers, D.C., Kaplan, J.D., Meyer, M.W et al. (1998). Geographic trend in mercury measured in common loon feathers and blood. Environmental Toxicology and Chemistry 17, 173-183. 

Evers, D.C., Savoy, L.J., and DeSorbo, C.R. et al. (2008). Adverse effects from environmental mercury loads on breeding common loons. Ecotoxicology 17, 69-81. 

Evers, D.C., Taylor, K.M, and Major, A. et al. (2003). Common loon eggs as indicators of methyhnercury availability in North America. Ecotoxicology 12, 69-82. 

Founmer, F., Karasow, W.H., and Kenow, K.P. et al. (2002). The oral availability and toxicokinetics of methyl mercury in common loon chicks. Comparative Biochemistry and Physiology, Part A 133, 703-714. 

Kenow, K.P., Grasman, K.A., and Hines, R.K. et al. (2007). Effects of methylmercury exposure on the immune function of common loons. Environmental Toxicology and Chemistry 26, 1460-1469. 

Scheuhammer, A.M., Basu, N., and Burgess, N.M. et al. (2008). Relationships among mercury, selenium, and neurochemical parameters in common loons and bald eagles. Ecotoxicology 17, 93-102. 

Barr JF. 1996. Aspects of common loon (Gavia immer) feeding biology on its breeding ground. Hydrobiologia 321 119-144. 

FIGURE 5.2 Continental cross-section of MeHg bioavaUability in common loon blood and eggs. Mercury concentrations are arithmetic means and associated 1 SD in ppm, ww. Sample size in parentheses are first eggs and then blood. Source From Evers et al. 1998, 2003b.)... 

In birds, a brain mercury concentration of less than 2 ppm wet weight was associated with reduced egg laying, and impaired nest and territory fidelity in common loons (Barr 1986). Black duck embryos with brain mercury concentrations of 4 to 6 ppm failed to hatch (Finley and Stendall 1978). Brain mercury concentrations of 20 ppm caused 25% mortality in mercury-exposed zebra finches (Scheu-hammer 1988). 

Lake Common loon Adult Blood, egg Widespread distribution and easily studied large existing database sensitivity to Hg existing database for continental Hg exposure and lab and field effects... 

Barr JF. 1986. Population dynamics of the Common Loon (Gavia immer) associated with mercury-contaminated waters in northwestern Ontario. Canadian Wildlife Service Occasional Paper 56. 

Champoux L, Masse D, Evers DC, Lane O. (In press). Assessment of mercury exposure and potential effects in common loons in Quebec. Hydrobiologia. 

Counard CJ. 2000. Mercury exposure and effects on Common Loon Gavia immer) behavior in the Upper Midwestern United States. University of Minnesota. MS thesis. 

Ensor KL, Helwig DD, Wemmer LC. 1992. Mercury and lead in Minnesota common loons (Gavia immer). Minnesota Pollution Control Agency Water Quality Division. 

Evers D, Lane O, Savoy L, Goodale W. 2004. Assessing the impacts of methylmercury on piscivorous wildlife using a wildlife criterion value based on the common loon, 1998-2003. Biodiversity Research Institute (Report BRI2004-05). 

Evers DC. 2004. Status assessment and conservation plan for the Common Loon (Gavia immer) in North America. US Fish and Wildlife Service Technical Report. 

Evers DC, Jodice P. 2002. Winter population dynamics of Common Loons on the Florida gulf coast a preliminary report. Unpublished report, alaska.fws.gov/mbsp/mbm/ loons/pdf/Common Loon Status Assessment.pdf... 

Evers DC, Kaplan JD, Meyer MW, Reaman PS, Braselton WE, Major A, Burgess N, Scheu-hammer AM. 1998. Geographic trends in mercury measured in common loon feathers and blood. Environ Toxicol Chem 17 173-183. 

Evers DC, Reaman P. 1997. A comparison of mercury exposure between artificial impoundments and natural lakes measured in Common Loons and their prey, sediments, and game fish. BioDiversity Research Institute, Fahnouth, ME. 

Fevold BM, Meyer MW, Rasmussen PW, Temple SA. 2003. Bioaccumulation patterns and temporal trends of mercury exposure in Wisconsin common loons. Ecotoxicology 12 83-93. 

Fournier F, Karasov WH, Kenow KP, Meyer MW, Hines RK. 2002. The oral bioavaHability and toxicokinetics of methylmercury in common loon (Gavia immer) chicks. Comp Biochem Physiol A Mol Integr Physiol 133 703-714. 

Fox GA, Yonge KS, Sealy SG. 1980. Breeding performance, pollutant burden, and eggshell thinning in Common Loons Gavia immer nesting on a boreal forest lake. Omis Scand 11 243-248. 

Kenow KP, Gutreuter S, Elines RK, Meyer MW, Fournier F, Karasov WEI. 2003. Effects of methyl mercury exposure on the growth of juvenile common loons. Ecotoxicology 12 171-182. 

Meyer MW, Evers DC, Daulton T, Braselton WE. 1995. Common loons (Gavia immer) nesting on low pH lakes in northern Wisconsin have elevated blood mercury content. Water Air Soil Pollut 80 871-880. 

Meyer MW, Evers DC, Hartigan JJ, Rasmussen PS. 1998. Patterns of Common Loon Gavia immer) mercury exposure, reproduction, and survival in Wisconsin, USA. Environ Toxicol Chem 17 184-191. 

Nocera JJ, Taylor PD. 1998. In situ behavioral response of common loons associated with elevated mercury (Hg) exposure. Conserv Ecol 2 10-17. 

Olsen B, Evers DC, DeSorbo C. 2000. The effect of methylated mercury on the diving frequency of the common loon. J Ecol Res 2 67-72. 

Piper WH, Paruk JD, Evers DC, Meyer MW, Tischler KB, Klich M, Hartigan JJ. 1997. Local movements of color-marked common loons. J Wildl Manage 61 1253-1261. 

Scheuhammer AM, Atchison CM, Wong AHK, Evers DC. 1998a. Mercury exposure in breeding common loons (Gavia immer) in central Ontario, Canada. Environ Toxicol Chem 17 191-196. 

Scheuhammer AM, Wong AEI, Bond D. 1998b. Mercury and selenium accumulation in common loons (Gavia immer) and common mergansers (Mergus merganser) from eastern Canada. Environ Toxicol Chem 17 197-201. 

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