Helminths in Magellanic Penguin (Spheniscus magellanicus) Nest Soil in One of the Southernmost Breeding Colonies at Martillo Island, Tierra Del Fuego, Argentina

This study provides the first record of helminth prevalence associated with Magellanic penguins (Spheniscus magellanicus) at the southernmost limit of their distribution, in the Beagle Channel, Argentina. Using a non-invasive and indirect nest soil sampling approach, we detected multiple helminth morphotypes, including nematodes, cestodes, trematodes, and acanthocephalans. Nematodes were the most frequently encountered group. Helminth load was greater during chick rearing than in the post-breeding period, likely due to increased fecal deposition and favorable environmental conditions. Parasite occurrence also varied across colony erosion zones shaped by penguin activity and natural processes, suggesting that microhabitat characteristics influence helminth persistence. These findings underscore the utility of soil sampling for monitoring temporal patterns of parasite exposure, particularly in remote wildlife populations, highlighting the need for continued surveillance of penguin health. Future research integrating direct parasitological and molecular techniques will improve taxonomic resolution and advance the understanding of parasite transmission dynamics.