Table 2.

To examine the possible effect of taxonomic grouping on the rate of loss of CBG-bound glucocorticoids (cortisol or corticosterone) to dextran-coated charcoal (DCC) during the charcoal separation method, we ran the charcoal adjustment assay (see Methods) in selected bird and mammal species

		Slope	% loss at 15 min	Glucocorticoid used
Single batch of DCC	Murre	−0.019	49%	Corticosterone
	Kittiwake	−0.029	63%	Corticosterone
	Savannah sparrow	−0.018	47%	Corticosterone
	Bottlenose dolphin	−0.012	35%	Cortisol
	Weddell seal	−0.009	26%	Cortisol
	Antarctic fur seal	−0.006	20%	Cortisol
	Sea otter	−0.010	29%	Cortisol
Separate batches of DCC	Deer mouse	−0.011	32%	Corticosterone
	Antarctic fur seal	−0.008	24%	Cortisol
	Weddell seal	−0.011	32%	Cortisol
	California sea lion	−0.007	23%	Cortisol
	Crabeater seal	−0.013	37%	Cortisol
	Australian fur seal	−0.008	23%	Cortisol

All species in the ‘single batch’ rows were run at the same time, using the same DCC. The species in the ‘separate batch’ rows were done in advance of measuring the MCBC for the survey of marine mammal binding capacities, except the deer mouse (Peromyscus maniculatus) which was from previous unpublished data. Rate of loss was defined as the slope of a linear regression of the log (specific binding) in counts per minute versus length of DCC exposure (minutes). All slopes were significantly different from 0 (P < 0.01)