Environmental Toxicology and Pharmacology 23 (2007) 347–349 Short communication Exposure of birds to cholinesterase-inhibiting pesticides following a forest application for tick control M´ onica Mart´ ınez-Haro, Javier Vi˜ nuela, Rafael Mateo ∗ Instituto de Investigaci´ on en Recursos Cineg´ eticos (IREC), CSIC-UCLM-JCCM, Ronda de Toledo s/n, 13071 Ciudad Real, Spain Received 27 June 2006; received in revised form 17 November 2006; accepted 30 November 2006 Available online 9 December 2006 Abstract A mixture of malathion (4%), carbaryl (2%) and cypermethrin (4%) was applied as dry powder to forest and grasslands at a rate of 5 kg/ha for tick control in 1500 ha 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. © 2006 Elsevier B.V. All rights reserved. Keywords: Organophosphorus; Carbamate; Parasites; Diseases; Wildlife 1. Introduction Ticks are vectors of important diseases to animals and humans (Estrada-Pe˜ na and Jongejan, 1999) and common parasites in wildlife in areas with high density of animals or with spa- tial aggregation around artificial feeders (Ginsberg and Zhioua, 1999). There are different methods to control ticks, such as reduction of animal densities, management of vegetation, appli- cation of acaricides (Mount et al., 1968), vaccination (de la Fuente and Kocan, 2003), and use of biological pesticides (Polar et al., 2005). Among these, the most used method is the treat- ment with acaricides, which can be used directly on animals by dip baths, topical-self, oral or injectable applications, or indi- rectly by area-wide applications of the habitat with pesticides like organophosphorus compounds (OP), carbamates (CB), and pyrethroids. The anti-ChE pesticides, like OP and CB, are widely used in agriculture and forest, and the adverse effects on different non-target species, including humans, have been studied exten- sively (Busby et al., 1991; Pe˜ na et al., 1996; Mineau et al., 1999; Fleischli et al., 2004). Their use for tick control by top- ical or area-wide applications implies the risk of poisoning of non-target species of vertebrates because of the high toxicity ∗ Corresponding author. Tel.: +34 926295450; fax: +34 926295451. E-mail address: rafael.mateo@uclm.es (R. Mateo). of some of these compounds (Mineau et al., 1999). Although the main effect of these pesticides is the inhibition of the acetyl- cholinesterase (AChE) present at the nervous tissue (Ecobichon, 1996), the monitoring of the plasma ChE activity has been fre- quently used as a sensitive non-destructive biomarker to study the exposure to anti-ChE pesticides in wild birds (McInnes et al., 1996; Maul and Farris, 2005). The aim of this work was to assess the effects on wildlife of the area-wide application of a mixture of pesticides against ticks (mainly Hyalomma sp. and Rhipicephalus sp.) in a deer hunting estate in the south of Spain. 2. Materials and methods 2.1. Study area The study area is a hunting estate of 3000 ha close to the Natural Park of Los Alcornocales in the province of C´ adiz, in the southwest of the Iberian Peninsula (Andalucia, Spain). The habitat is a Mediterranean woodland characterized by the presence of cork oak (Quercus suber L.), evergreen oak (Quercus ilex) and wild olive tree (Olea europaea var. sylvestris) with scrubland areas and scattered pastures. The large game species present in the area are the red deer (Cervus elaphus), roe deer (Capreolus capreolus) and European wild boar (Sus scrofa). 2.2. Application dose A total of 1500 ha were treated between 1 and 15 June 2005 with a dry powder formulation containing carbaryl (1-naphthyl methylcarbamate) (2%), malathion (S-1,2-bis(ethoxycarbonyl)ethyl O,O-dimethyl phosphorodithioate) 1382-6689/$ – see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.etap.2006.11.011