title: Excretion patterns of coccidian oocysts and nematode eggs during the reproductive season in Northern Bald Ibis (Geronticus eremita).
abstract: Individual reproductive success largely depends on the ability to optimize behaviour, immune function and the physiological stress response. We have investigated correlations between behaviour, faecal steroid metabolites, immune parameters, parasite excretion patterns and reproductive output in a critically endangered avian species, the Northern Bald Ibis (Geronticus eremita). In particular, we related haematocrit, heterophil/lymphocyte ratio, excreted immune-reactive corticosterone metabolites and social behaviour with parasite excretion and two individual fitness parameters, namely, number of eggs laid and number of fledglings. We found that the frequency of excretion of parasites' oocysts and eggs tended to increase with ambient temperature. Paired individuals excreted significantly more samples containing nematode eggs than unpaired ones. The excretion of nematode eggs was also significantly more frequent in females than in males. Individuals with a high proportion of droppings containing coccidian oocysts were more often preened by their partners than individuals with lower excretion rates. We observed that the more eggs an individual incubated and the fewer offspring fledged, the higher the rates of excreted samples containing coccidian oocysts. Our results confirm that social behaviour, physiology and parasite burden are linked in a complex and context-dependent manner. They also contribute background information supporting future conservation programmes dealing with this critically endangered species.
authors: Core Facility Konrad Lorenz Forschungsstelle for Behaviour and Cognition, University of Vienna, Fischerau 11, 4645 Grünau im Almtal, Austria ; Department of Behavioural Biology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
authors: Didone
authors: D
authors: Frigerio
authors: Core Facility Konrad Lorenz Forschungsstelle for Behaviour and Cognition, University of Vienna, Fischerau 11, 4645 Grünau im Almtal, Austria.
authors: Lara
authors: L
authors: Cibulski
authors: Core Facility Konrad Lorenz Forschungsstelle for Behaviour and Cognition, University of Vienna, Fischerau 11, 4645 Grünau im Almtal, Austria ; Game & Wildlife Conservation Trust, The Coach House, Eggleston Hall, Barnard Castle, DG12 0AG UK.
authors: Sonja C
authors: SC
authors: Ludwig
authors: Core Facility Konrad Lorenz Forschungsstelle for Behaviour and Cognition, University of Vienna, Fischerau 11, 4645 Grünau im Almtal, Austria ; Department of Animal Production, Neiker-Tecnalia, Vitoria-Gasteiz, Spain.
authors: Irene
authors: I
authors: Campderrich
authors: Core Facility Konrad Lorenz Forschungsstelle for Behaviour and Cognition, University of Vienna, Fischerau 11, 4645 Grünau im Almtal, Austria ; Department of Behavioural Biology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
authors: Kurt
authors: K
authors: Kotrschal
authors: Core Facility Konrad Lorenz Forschungsstelle for Behaviour and Cognition, University of Vienna, Fischerau 11, 4645 Grünau im Almtal, Austria ; Animal and Environment Research Group, Department of Life Sciences, Anglia Ruskin University, Cambridge, UK.
authors: Claudia A F
authors: CA
authors: Wascher
keywords: Geronticus eremita; Northern Bald Ibis; Parasite burden; Reproduction