Ectoparasite load in growing young and adult barnacle geese in the Dutch delta - Research Report 2

By extending their arctic breeding locations to more temperate latitudes such as the Dutch delta, barnacle geese expose themselves to “dirtier” environments in which a higher pressure of ectoparasites could occur. Ectoparasites make up a very diverse group in the animal kingdom, and every vertebrate organism carries one or more species. However, they are highly unappreciated by biologists. As far as we know this is the first detailed study investigating ectoparasite load in barnacle geese. In this study we sampled ectoparasites on barnacle geese caught in the Dutch delta in order to make an indication of the ectoparasite load carried by the barnacle goose and the ectoparasite species which inhabit it. Five species of ectoparasites where found (2 Amblycera and 3 Ischnocera. The blood-feeding Amblycera accounted for merely 6% of the total. The Ischnoceran Anaticola anseris was most numerous and accounted for 45% of the total. For the 5 ectoparasite species we show densities, presence / absence, co-occurrence. We also show that as goslings mature, the ectoparasite composition in their plumage changes. We conclude that although Amblycera, are blood-feeding and scarce, they are still more harmful to the goose by acting as an intermediate host and vector, spreading more harmful endoparasites. Ischnocera are indicative to the goose’s health and are not presumed to transfer any diseases.