Poor consideration of sites: Turbines can cause disruption to TV and radio signals and even the migration of birds when they are not positioned correctly.
They want to scrape bits of tissue from planes, discover which birds are most often being struck, and thus work out which bird-migration routes to avoid.
Spanish company Pateria de Sousa, in Badajoz province, is seen as more ethical because it makes its foie gras by slaughtering the birds at a time when they have naturally eaten more to create reserves for what would have been migration.