Exposure of birds to cholinesterase-inhibiting pesticides following a forest application for tick control.

A mixture of malathion (4%), carbaryl (2%) and cypermethrin (4%) was applied as dry powder to forest and grasslands at a rate of 5kg/ha for tick control in 1500ha of a deer hunting estate in the south of Spain. The effect on plasma cholinesterase (ChE) of house sparrow and nightingale, and brain ChE of red-legged partridge was studied. Plasma ChE was lower after the treatment in passerine birds, but brain AChE was not affected in partridges. The body condition of house sparrows was significantly lower after the treatment.