Metabolism of radiocaesium in red grouse

Red grouse eat a natural diet mostly of heather, a dwarf shrub which accumulates radiocaesium. Captive grouse were fed a diet, comprising 60% heather contaminated with Chernobyl radiocaesium, containing about 1500 Bq kg−1 of radiocaesium. Intake and excretion of radiocaesium reached equilibrium after 20–23 days and its biological half-life was 10–11 days, with about 23% of the radiocaesium in the diet being absorbed by the bird. Transfer coefficients for both captives and wild birds were about 10 days kg−1. Radiocaesium activity concentrations in wild birds reflected those in their diet and it is suggested that the sampling of birds shot for sport could form an efficient means of monitoring radiocaesium levels in heather-dominated uplands in the UK.