title: Little field evidence of direct acute and short-term effects of current pesticides on the grey partridge.
abstract: Direct lethal and sublethal effects of pesticides on farmland birds' populations are recurring questions and largely debated. In this context, we conducted an innovative study combining radiotelemetry, farmer surveys, residue analyses on carcasses and modelling to assess the unintentional effects of pesticides on terrestrial birds. We chose the grey partridge Perdix perdix as a case study because this typical bird of European cereal ecosystems is highly exposed to pesticides. In this paper we focused on acute and short-term impacts of pesticides on adult mortality during spring and summer in a one-substance approach (multiple exposure were not studied here) but for a large variety of active substances (a.s.) actually used in cultivated farmland of Northern France. The fate and the location of 529 partridges were monitored twice a day from early March to late August 2010 and 2011 on 12 sites (14,500 ha). Their daily potential exposure to 183 a.s. was determined by overlapping birds' habitat use and daily pesticide application data. Based on this procedure, we calculated mortality rates within 10 days following a potential exposure for 157 different a.s.. 5 a.s. were associated with a "10-day mortality rate" higher than 10% but a single one (thiacloprid) is reported to be highly toxic to birds. We recorded 261 mortalities among which 94 carcasses were in suitable condition for residue analyses. We detected at least one a.s in 39.4% of carcasses. However, only 2 mortality cases were attributed to poisoning (carbofuran). Furthermore, modelling results showed that these lethal pesticide-related poisonings decreased the population growth rate by less than 1%. In conclusion, we did not point out important direct acute and short-term effects of pesticides currently used by farmers during the breeding season on the grey partridge. This is discussed with regards to the complexity of potential effects in operational conditions.
authors.affiliation: National Game and Wildlife Institute (ONCFS), Research Department, Saint Benoist, 78610 Auffargis, France. Electronic address: florian.millot@oncfs.gouv.fr.
authors.forename: Florian
authors.initials: F
authors.lastname: Millot
authors.affiliation: College of Veterinary Medicine, Toxicology, Ecole Nationale Vétérinaire de Lyon, 1, av Bourgelat, 69280 Marcy l'étoile, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Berny
authors.affiliation: National Game and Wildlife Institute (ONCFS), Research Department, Saint Benoist, 78610 Auffargis, France.
authors.forename: Anouk
authors.initials: A
authors.lastname: Decors
authors.affiliation: National Game and Wildlife Institute (ONCFS), Research Department, Saint Benoist, 78610 Auffargis, France.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Bro
mesh_terms: D000818:Animals; D001717:Birds; D001947:Breeding; D017753:Ecosystem; D005260:Female; D005602:France; D046094:Galliformes; D040362:Geographic Information Systems; D008297:Male; D008962:Models, Theoretical; D010573:Pesticide Residues / Q000032:analysis* / Q000633:toxicity*; D010575:Pesticides / Q000032:analysis / Q000633:toxicity; D011157:Population Dynamics; D011795:Surveys and Questionnaires; D013686:Telemetry
chemical_list: D010573:Pesticide Residues; D010575:Pesticides
keywords: Bird; Cultivated landscape; Modelling; Mortality; Radiotracking; Residue analyses