Effects of weather on daily body mass regulation in wintering dunlin
John P. Kelly1,*,
Nils Warnock2,
Gary W. Page2 and
Wesley W. Weathers3
1 Cypress Grove Research Center, Audubon Canyon Ranch, PO Box 808, Marshall, CA 94940, USA,
2 Point Reyes Bird Observatory, 4990 Shoreline Highway, Stinson Beach, CA 94970, USA and
3 Department of Animal Sciences, University of California, Davis, CA 95616, USA

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Fig. 1. Scatterplot of intraseasonal body mass change in captive dunlin at Tomales Bay, California, 19978 and 19989. The trend line was estimated using LOWESS, a locally weighted regression algorithm (Cleveland, 1979 ); smoothing parameter, F=0.25 of data scanned for each fitted value.
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Fig. 2. Quadratic trends in mass loss of fasting dunlin allowed to dry after periods of artificial rainfall, indicating water retention in plumage (top) and accelerated body mass loss (bottom). Open symbols and broken lines represent rainfall birds; solid symbols and solid lines represent control birds. Triangles and bold lines represent responses to 8 h of artificial rainfall; circles and thin lines represent responses to 18 h of artificial rainfall. r2>0.99.
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Fig. 3. Sensitivity analysis of rainfall-related increases in activity costs, adjusted for possible external water mass, in captive dunlin under ad libitum feeding conditions. Difference in activity cost = costs on days with rain costs on days without rain. Gross utilization efficiency = assimilation efficiency x efficiency of utilization of metabolizable energy. Solid lines indicate varying energy density of stored body tissue, labeled as the proportion of mass that is fat; dotted lines indicate lower 95 % confidence intervals for each energy density.
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© The Company of Biologists Ltd 2002