Nest-Building Behaviour by Chimpanzees (Pan troglodytes verus) in the Non-Protected Area of Diaguiri (Kedougou, Senegal): Implications for Conservation

Abstract

Diaguiri is a non-protected area situated in south-eastern Senegal. Chimpanzees (Pan troglodytes verus) have been living here since 1999 but information on the characteristics of their nest sites have been lacking until now. Furthermore, we implemented nest survey methods recently standardised to arid landscapes during a national chimpanzee survey. Variations in nest decay rates are poorly understood in savanna-woodland mosaic habitats. This study aims to describe in Diaguiri: (1) the distribution of chimpanzee nests and the location of their core sleeping area, (2) the tree species used for nest building, (3) the association between nests and nesting tree heights, and (4) differences in nest decay rates between habitats. We surveyed 43 km of chimpanzee nesting habitats and recorded 871 nests in gallery forest and woodland habitats between March 2015 and June 2016. Diaguiri chimpanzees used at least 17 tree species for nest building, and 58.8% of nests were in only 3 tree species: Pterocarpus erinaceus, Anogeissus leiocarpus and Diospyros mespiliformis. Nest decay rate was faster in gallery forests than in woodlands. These data are of great value for understanding habitat use by a Critically Endangered subspecies of savanna chimpanzee, for population density estimates of the species and for conservation programmes in this region and in savanna biomes.

Deciding Where to Sleep: Spatial Levels of Nesting Selection in Chimpanzees (Pan troglodytes) Living in Savanna at Issa, Tanzania

“…Social factors, food abundance and availability, seasonality, and vegetation types in the habitat have been proposed to influence the selection of sleeping sites in primates (Anderson 1984(Anderson , 2000, including chimpanzees (Badji et al 2018;Baldwin et al 1982;Barca et al 2018;Basabose and Yamagiwa 2002;Carvalho et al 2015;Furuichi and Hashimoto 2004;Goodall 1986;Granier et al 2014;Hakizimana et al 2015;Hernandez-Aguilar 2009;Koops et al 2012;Ndiaye et al 2018;Ogawa et al 2007Ogawa et al , 2014. Social factors, such as engaging in territory patrols or guarding females with swollen sexual skin influence male chimpanzees' decisions of where to nest (Goodall 1986).…”

An Investigation into the Influence of Different Types of Nesting Materials upon the Welfare of Captive Chimpanzees (Pan troglodytes)

“…The relative frequency of agonistic behaviours was lowest during Treatment 4 (shredded newspaper) and Treatment 6 (cotton sheets plus shredded newspaper), and BCI was highest during Treatment 4, suggesting that chimpanzees’ welfare is higher when presented with shredded newspaper. Although leaves and branches are used by wild chimpanzees during nest building [ 22 , 23 ] we deduce that captive individuals engage in many more positive behaviours than simply building a nest when provisioned with shredded newspaper. Common positive behaviours observed with this material were solitary and social play, chewing, mouth tearing and hand manipulation (we also noted that even during other treatments, nest building was only one of several behaviours exhibited).…”

“…The materials tested were leaves and branches, long grass, cotton sheets and shredded newspaper. We predicted that (2) the chimpanzees’ welfare would be most enhanced when receiving leaves and branches, seeing as this is the material used by wild individuals who bend and break larger and smaller branches of preferred tree species to construct their nests [ 22 , 23 ]. The third aim was to evaluate if the chimpanzees’ welfare differed when supplied with two materials, instead of one: leaves and branches with long grass, and cotton sheets with shredded newspaper.…”

Informing Protection Efforts for Critically Endangered Chimpanzees (<b><i>Pan troglodytes verus</i></b>) and Sympatric Mammals amidst Rapid Growth of Extractive Industries in Senegal

“…Specifically, the Senegalese chimpanzees are at risk of extinction due to the proliferation of extractive industries, such as gold and iron ore mining, and intensifying competition with people over natural resources [Pruetz, 2014;Waller and Pruetz, 2016;Boyer-Ontl, 2017;Ndiaye et al, 2018a, b]. Conservation and management stakeholders must understand how savannah chimpanzees make a living in protected and unprotected lands during the rise of extractive industries in Senegal by using basic research on savannah chimpanzee behavior and ecology [Pruetz and Bertolani, 2009;Lindshield et al, 2017;Ndiaye et al, 2018a;Wessling et al, 2018], extractive industries in other great ape range countries [Morgan et al, 2013;Arcus Foundation, 2014;Kormos et al, 2014], and ground-truthed assessments of local threats [Ndiaye, 2011;Ndiaye et al, 2018b].…”