Impact of fenthion on nontarget birds during quelea control in Kenya

Two nesting colonies of Quelea quelea in Kenya, 10 and 40 ha in size, were sprayed with 40 and 100 L of Queletox (60% fenthion), respectively. Predatory and insectivorous birds were exposed to short-lived, but severe and potentially harmful, residues. In both colonies, quelea died during a 4-7 day period. In the larger colony, dead and dying birds were found over an area of ≤17 days after spraying, only 2 were found moribund, but based on cholinesterase depression, 16 of 23 raptors examined after spraying were thought to have been exposed. -from Authors