TY - JOUR
T1 - Determining seabird body condition using nonlethal measures
AU - Jacobs, Shoshanah R.
AU - Elliott, Kyle
AU - Guigueno, Mélanie F.
AU - Gaston, Anthony J.
AU - Redman, Paula
AU - Speakman, John R.
AU - Weber, Jean Michel
N1 - We thank K. Ashcroft, M. Barrueto, S. Charest, J. Nakoolak, K. O’Donovan, J. Ringrose, A. Ronston, K. Woo, and P. Woodward for their help in the field. S.R.J. benefited from the University of Ottawa Doctoral Research Award, Northern Scientific Training Program, Weinberger Award for Environmental Research, Heather Glendinning McMurter Award for Environmental Research, and Maas Family Scholarship. K.H.E. benefited from funding provided by Natural Sciences and Engineering Research Council (NSERC) Postgraduate (M) and Vanier Awards, NSERC Northern Research Internship, W. Garfield Weston Award for Northern Research, American Ornithologist Union’s Research Grant, Northern Scientific Training Program (Malcolm Ramsay Award), Mountain Equipment Co-op Studentship, Arctic Institute of North America Grant-in-aid and Jennifer Robinson Scholarship, Society of Canadian Ornithologists/Bird Studies Canada Taverner and Baillie Awards, and American Museum of Natural History Frank M. Chapman Award. Additional financial support came from Environment Canada and the University of Manitoba. R. Armstrong at the Nunavut Research Institute and C. Eberl and M. Mallory of Environment Canada provided logistical support. Assistance with transportation was provided by the Polar Continental Shelf Project of Energy, Mines, and Resources Canada. We thank G. Anderson, T. Diamond, J. Hare, J. Jehl, the Jim and Jane Lab (Jim, Jane, Marci, Olwyn, Nadine, Ryan, and Molly), and an anonymous reviewer for constructive comments on an earlier draft of the manuscript.
PY - 2012/1/3
Y1 - 2012/1/3
N2 - Energy stores are critical for successful breeding, and longitudinal studies require nonlethal methods to measure energy stores ("body condition"). Nonlethal techniques for measuring energy reserves are seldom verified independently.We compare body mass, size-corrected mass (SCM), plasma lipids, and isotopic dilution with extracted total body lipid content in three seabird species (thick-billed murres Uria lomvia, all four measures; northern fulmars Fulmarus glacialis, three measures; and black-legged kittiwakes Rissa tridactyla, two measures). SCM and body mass were better predictors of total body lipids for the species with high percent lipids (fulmars; R 2 = 0.5-0.6) than for the species with low percent lipids (murres and kittiwakes; R 2 = 0.2-0.4). The relationship between SCMand percent body lipids, which we argue is often a better measure of condition, was also poor (R 2 = 0.2) for species with low lipids. In a literature comparison of 17 bird species, percent lipids was the only predictor of the strength of the relationship between mass and total body lipids; we suggest that SCM be used as an index of energy stores only when lipids exceed 15% of body mass. Across all three species we measured, SCM based on the ordinary least squares regression of mass on the first principal component outperformed other measures. Isotopic dilution was a better predictor of both total body lipids and percent body lipids than were mass, SCM, or plasma lipids in murres. Total body lipids decreased through the breeding season at both sites, while total and neutral plasma lipid concentrations increased at one site but not another, suggesting mobilization of lipid stores for breeding. A literature review showed substantial variation in the reliability of plasma markers, and we recommend isotopic dilution (oxygen-18, plateau) for determination of energy reserves in birds where lipid content is below 15%.
AB - Energy stores are critical for successful breeding, and longitudinal studies require nonlethal methods to measure energy stores ("body condition"). Nonlethal techniques for measuring energy reserves are seldom verified independently.We compare body mass, size-corrected mass (SCM), plasma lipids, and isotopic dilution with extracted total body lipid content in three seabird species (thick-billed murres Uria lomvia, all four measures; northern fulmars Fulmarus glacialis, three measures; and black-legged kittiwakes Rissa tridactyla, two measures). SCM and body mass were better predictors of total body lipids for the species with high percent lipids (fulmars; R 2 = 0.5-0.6) than for the species with low percent lipids (murres and kittiwakes; R 2 = 0.2-0.4). The relationship between SCMand percent body lipids, which we argue is often a better measure of condition, was also poor (R 2 = 0.2) for species with low lipids. In a literature comparison of 17 bird species, percent lipids was the only predictor of the strength of the relationship between mass and total body lipids; we suggest that SCM be used as an index of energy stores only when lipids exceed 15% of body mass. Across all three species we measured, SCM based on the ordinary least squares regression of mass on the first principal component outperformed other measures. Isotopic dilution was a better predictor of both total body lipids and percent body lipids than were mass, SCM, or plasma lipids in murres. Total body lipids decreased through the breeding season at both sites, while total and neutral plasma lipid concentrations increased at one site but not another, suggesting mobilization of lipid stores for breeding. A literature review showed substantial variation in the reliability of plasma markers, and we recommend isotopic dilution (oxygen-18, plateau) for determination of energy reserves in birds where lipid content is below 15%.
UR - http://www.scopus.com/inward/record.url?scp=84855822096&partnerID=8YFLogxK
U2 - 10.1086/663832
DO - 10.1086/663832
M3 - Review article
C2 - 22237292
AN - SCOPUS:84855822096
SN - 1522-2152
VL - 85
SP - 85
EP - 95
JO - Physiological and Biochemical Zoology
JF - Physiological and Biochemical Zoology
IS - 1
ER -