Excretion patterns of coccidian oocysts and nematode eggs during the reproductive season in Northern Bald Ibis (Geronticus eremita)

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

Classifying chimpanzee (Pan troglodytes) landscapes across large scale environmental gradients in Africa

Primates are sometimes categorized in terms of their habitat. Although such categorization can be over-simplistic, there are scientific benefits from the clarity and consistency that habitat categorization can bring. Chimpanzees (Pan troglodytes) inhabit various environments, but researchers often refer to ‘forest’ or ‘savanna’ chimpanzees. Despite the wide use of this forest-savanna distinction, clear definitions of these landscapes for chimpanzees, based on environmental variables at study sites or determined in relation to existing bioclimatic classifications, are lacking. The robustness of the forest-savanna distinction thus remains to be assessed. We review 43 chimpanzee study sites to assess how the landscape classifications of researchers fit with the environmental characteristics of study sites and with three bioclimatic classifications. We use scatterplots and Principal Components 15 Analysis to assess the distribution of chimpanzee field sites along gradients of environmental 16 variables (temperature, rainfall, precipitation seasonality, forest cover and satellite-derived 17 Hansen tree cover). This revealed an environmental continuum of chimpanzee study sites 18 from savanna to dense forest, with a rarely acknowledged forest mosaic category in between, 19 but with no natural separation into these three classes and inconsistencies with the bioclimatic 20 classifications assessed. The current forest–savanna dichotomy therefore masks a progression 21 of environmental adaptation for chimpanzees, and we propose that recognizing an additional, 22 intermediate ‘forest mosaic’ category is more meaningful than focusing on the ends of this 23 environmental gradient only. Future studies should acknowledge this habitat continuum, place their study sites on the forest–savanna gradient, and include detailed environmental data to support further attempts at quantification