The levels of persistent, lipophilic pollutants in different organs and body-fluids of birds are governed by partitioning, i.e. the levels are correlated. This implies that it may be possible to estimate the total body-burden of chlorinated hydrocarbons, without sacrificing the animals, by examining the levels in secretory fluid. This hypothesis was tested on the goosander, a fish-eating waterfowl. We found that levels of PCB and DDE in secretions from the uropyginal gland were linearly related to levels in the breast muscle. Thus, by estimating the amounts of persistent pollutants in water-repellent secretions, the total body-burden could be calculated.