New paper in Applied Animal Behaviour Science

Sublethal effects of pesticide residues differ between strains of captive Grey partridge: Consequences in terms of rearing conditions
Agathe Gaffard, Clotilde Loiseau, Vincent Bretagnolle, Olivier Pays, Jérôme Moreau

DOI : https://doi.org/10.1016/j.applanim.2022.105791 

Abstract : Over the last 50 years, farmland bird populations have declined steeply in Europe and North America. Reintroduction or reinforcement for populations unable to self-maintain are popular management tools to overcome extinction risk through captive rearing and release. However, released birds tend to have lower survival rates than their wild conspecifics. Here, we aimed to mimic the diet shift that Grey partridge (Perdix perdix) encounters once released (poultry food to natural grain) and compared (i) differences in responses to this transition depending on strain (wild or farm) and (ii) the consequences of ingesting organic or conventional grains on individual body mass, haematocrit and behavioural traits (anti-predator responses, activity, exploration) that are likely critical for post-release survival. Our experimental procedure involved 40 farm-strain and 40 wild-strain partridges fed with commercial poultry food during early life then with wheat and corn for 3 months, from either organic or conventional (clopyralid residues) agriculture. The results suggest that the haematocrit and body mass index of farm-strain partridges were lower at the end of the experiment, probably due to diet shift. Birds fed conventional grains (with clopyralid residues) exhibited lower flight duration and flight initiation distance, and were more likely to translocate by running rather than flying. The findings suggest that, when rearing partridges of farm-strain origin, birds fed organic grains experience better post-release survival than birds fed conventional grains containing pesticide residues.