Kestrel (Falco tinnunculus) The geometric imply association of dieldrin with the livers of 374 kestrels located dead within the United Kingdom inside the period 1963 - 1977 was 1. 2 mg/kg (Cooke et al. , 1982). Some 50% with the kestrels observed dead contained less than 1 mg dieldrin/kg liver, 18% contained more than dix mg/kg, and 8% in excess of 20 mg/kg.