Lousy chicks: Chewing lice from the Imperial Shag, .

Forty-one imperial shag chicks were sampled for lice during the breeding season of 2014 in Punta León, Argentina. We found 2 lice species, infesting the body and present in the oral cavity of the birds. This constitutes the first host record for and the first record for the continental Argentina for . Ninety-three percent of the chicks were infested by at least one lice species. . was present in all of the lousy chicks, while infested 84.2% of them. The mean intensity was 29.5 and the range 1-129. There was no difference in prevalence, mean intensity or mean abundance between louse species. However, we found differences among the pattern of infestation of each species. Imperial shag chicks were infested by their parents during their first days of life by , mainly in nymphal stage and by as adult lice. Our results showed differences among lice species that could be related to the restrictions that lice from seabirds faced during their life cycle.