Movement ecology and health conditions of Brown skuas throughout their breeding period

GRAÑA GRILLI, M.; ALARCÓN, P.A.E.; IBÁÑEZ, A.E.

Iguazú

Congreso; I Ornithological Congress of the Americas; 2017

Breeding influences the nutritional and immunological condition of the parents due to itshigh degree of stress and energetic cost, and in central place foragers, through the restriction imposed to their movements and the reduction in their time for self-feeding. The development of the offspring increases its energetic requirements, leading to a higher energetic investment by the parents and then, to a negative effect on their42nutritional and immunological conditions. We studied the variation on the amount of movement and the nutritional and immunological condition in Brown skuas (Stercorarius antarcticus lonnbergi) breeding at Isla 25 de Mayo, Antarctica. The breeding period was divided in three stages: incubation (I), hatching (H) and fledging chicks (F). At each stage we characterized the amount of movement through the daily distance of flight (DDF), studied the nutritional conditions through the body mass and the concentration of metabolites associated to metabolic pathways of protein and lipids, and the immunological conditions through the heterophil:lymphocyte ratio. The DDF increased towards the last stage (I-H:p=0.46; H-F:p=0.02). Body mass decreased in Brown Skuas throughout their breeding period (I-H:p=0.03; H-F:p<0.01) and there was a decline of total proteins (I-H:p=0.01; H-F:p=0.03) and triglycerides (I-H:p=0.57; H-F:p=0.01), while the concentration of urea increased (I-H:p=0.00; H-F:p=0.01). Uric acid and NEFA as well as the heterophil:lymphocyte ratio did not change. This shows an increase in parents investment, especially towards the end of the breeding period, with a decrease in the general body condition that does not impact on the immunological condition at the level studied.