Do Large Birds Experience Previously Undetected Levels of Hunting Pressure in the Forests of Central and West Africa?

Do large birds experience previously undetected levels of hunting pressure in the forests of Central and West Africa? R OBIN C. WHYTOCK,RALPH B UIJ,MUNIR Z. VIRANI and B ETHAN J. MORGAN Abstract The commercial bushmeat trade threatens Introduction numerous species in the forests of West and Central Africa. Hunters shoot and trap animals, which are trans- umans have hunted for subsistence in the forests ported to rural and urban markets for sale. Village-based Hof Central and West Africa for millennia (Milner- 2003 surveys of hunter offtake and surveys of bushmeat markets Gulland et al., ). However, for many people living in have shown that mammals and reptiles are affected most, rural areas hunting has become an important source of followed by birds. However, hunters also consume some revenue, driven by the high demand for bushmeat among 2003 2005 animals in forest camps and these may have been over- urban populations (Fa et al., ; East et al., ). The looked in surveys that have focused on bushmeat extracted commercial bushmeat trade has become central to many fi from the forest. A number of studies have used indirect rural economies and a signi cant proportion of households methods, such as hunter diaries, to quantify this additional rely on hunting as their primary source of income (Wilkie & 1999 offtake but results can be difficult to verify. We examined Carpenter, ). The problem has been further exacerbated discarded animal remains at 13 semi-permanent hunting by the construction of roads for commercial logging op- camps in the Ebo Forest, Cameroon, over 272 days. Twenty- erations, which have made it easier to access previously one species were identified from 49 carcasses, of which birds unexploited wildlife populations and to transport meat to 2003 constituted 55%, mammals 43% and other taxa 2%. The urban markets (Milner-Gulland et al., ). As a result, mammals identified were typical of those recorded in wildlife is subject to increasingly unsustainable hunting previous bushmeat studies but we recorded several species pressure and numerous species have been extirpated locally 2002 2006 of birds rarely recorded elsewhere. Offtake of bird species (Bennett et al., ; Fa et al., ). increased with mean body mass. We extrapolated our Extensive bushmeat market and village-based surveys of ff ff results to the 34 known hunting camps in the Ebo Forest and hunter o take have shown that mammals are a ected most, 2006 estimated that a minimum of 97 birds are hunted annually followed by reptiles and birds (Fa et al., ; Willcox & 2 2007 2011 in a catchment area of c. 479 km . We conclude that some Nambu, ; Macdonald et al., ). However, these bird species may be hunted more frequently than previous surveys may fail to detect bushmeat not extracted from the research suggests and this has important conservation forest, such as animals consumed by hunters in camps, and ff 2001 implications for larger-bodied species such as raptors and may underestimate total o take (Fa & García Yuste, ; 2006 2010 2010 hornbills. Fa et al., ; Rist et al., ; Whytock & Morgan, ; Allebone-Webb et al., 2011). It can be difficult to follow Keywords Africa, birds, bushmeat, Cameroon, hornbills, hunters, for logistical reasons, and many operate in secrecy hunting, raptors because of the often illegal nature of their activities. For these reasons previous studies have used indirect methods, This paper contains supplementary material that can be such as interviews with hunters, questionnaires and diaries, found online at http://journals.cambridge.org to quantify the number of animals discarded in the forest or consumed in hunting camps (Fa & García Yuste, 2001; Kümpel, 2006; Willcox & Nambu, 2007; Rist et al., 2010; Allebone-Webb et al., 2011). Although there is evidence that these methods can be effective tools for monitoring hunting ROBIN C. WHYTOCK (Corresponding author) Ebo Forest Research Project, c/o BP 2008 2010 3055, Messa, Yaoundé, Cameroon, and Department of Biological and activities (Jones et al., ; Rist et al., ), if participants Environmental Sciences, University of Stirling, FK9 4LA, UK perceive a threat to their livelihood or fear legal repercus- E-mail [email protected] sions they may withhold information and results may be RALPH BUIJ Animal Ecology Department, Alterra Wageningen UR, inaccurate (Jones et al., 2008). In Cameroon, for example, a Wageningen, Netherlands number of frequently hunted species are legally protected MUNIR Z. VIRANI The Peregrine Fund, Boise, Idaho, USA, and Ornithology (Fa et al., 2006; Djeukam, 2012), and the increasing enforce- Section, Department of Zoology, National Museums of Kenya, Nairobi, Kenya ment of wildlife law (LAGA, 2012) means that hunters are BETHAN J. MORGAN Institute for Conservation Research, San Diego Zoo Global, Escondido, USA likely to be evasive when answering questions about their Received 15 August 2013. Revision requested 18 October 2013. activities. Thus, indirect measurements of hunter activity in Accepted 15 January 2014. First published online 24 July 2014. the forest may be unreliable. Oryx, 2016, 50(1), 76–83 © 2014 Fauna & Flora International doi:10.1017/S0030605314000064 Downloaded from https://www.cambridge.org/core. IP address: 170.106.33.42, on 28 Sep 2021 at 08:12:00, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0030605314000064 Hunting pressure on large birds 77 In the Ebo Forest, Cameroon, previous opportunistic chimpanzees Pan troglodytes ellioti, as well as the Critically observations of discarded animal remains in hunting camps Endangered Ebo gorilla Gorilla gorilla and Preuss’sred and informal discussions with hunters suggest that hunters colobus Procolobus preussi (Morgan, 2011). The proposed kill birds such as crowned eagles Stephanoaetus coronatus National Park also forms the largest contiguous forest block (Near Threatened; IUCN, 2013) for food when working within the Yabassi Important Bird Area, where several bird from forest camps (Whytock & Morgan, 2010). It is there- species on the IUCN Red List have been recorded, including fore possible that previous bushmeat surveys underesti- crowned eagle, grey-necked rockfowl Picathartes oreas and mated offtake of these and other birds, especially where grey parrot Psittacus erithacus (Fotso et al., 2001). For a de- animals consumed in camps were overlooked or under- tailed description of habitats and the anthropogenic history reported. Hunting is considered a significant threat to many of the Ebo Forest see Dowsett-Lemaire & Dowsett (2001) bird species in the tropical forests of Asia (Bennett et al., and Morgan (2008). 1997; McConkey & Chivers, 2004) but few studies have To date 34 semi-permanent hunting camps have been considered the fate of exploited bird populations in Central located in the Ebo National Park and its outliers (B. Morgan Africa. Crowned eagles, palm-nut vultures Gypohierax & E. Abwe, unpubl. data). We surveyed 13 of these: four angolensis and black-casqued hornbills Ceratogymna atrata and nine belonging to hunters from Mamba and Locndeng have been recorded occasionally in bushmeat surveys (Fa villages, respectively (Fig. 1). These villages were selected & García Yuste, 2001; Fa et al., 2006; Willcox & Nambu, because hunters were willing to cooperate with the study 2007). Although recorded in relatively low numbers these and the villages could be accessed within the logistical and conspicuous, large-bodied birds are found at naturally financial constraints of the project. Camps were distributed low densities and are therefore particularly vulnerable to throughout a large area of the forest, at varying distances hunting pressure. Furthermore, long-lived raptors such as from the nearest village or access roads, and because of this crowned eagles have low reproductive rates and even mini- were assumed to be a sufficiently representative sample. mal hunting pressure can significantly perturb the balance Anecdotal observations suggested that hunter behaviour in between fecundity and longevity (Owens & Bennett, 2000). the Ebo Forest (Supplementary Material 1) is similar to that Several birds are legally protected from hunting in described elsewhere in Central Africa (Fa & García Yuste, Cameroon (Djeukam, 2012) and a permit must be obtained 2001; Willcox & Nambu, 2007; Rist et al., 2010) and that before killing or capturing crowned eagles or palm-nut results are likely to be representative of the wider region. vultures. It is therefore essential that offtake of these species fi is quanti ed accurately to inform future conservation action Methods and legislative decisions (Trail, 2007; Carrete et al., 2009; 2010 Whytock & Morgan, ). Hunting camp surveys To enhance our understanding of the relative effect of bushmeat hunting on birds and other animals not extracted During 1 July 2011–28 March 2012 camps were searched for from the forest, we examined discarded animal remains in animal remains discarded by hunters. These dates were semi-permanent hunting camps in the Ebo Forest. We chosen to cover both the wet and dry seasons (sensu Fa et al., quantified the number of animals discarded by hunters and 2004, 2006), as hunting effort and species availability may predicted that large-bodied birds such as raptors and vary seasonally. The survey period covered 272 days, with hornbills would be recorded more frequently than other 94–265 survey days per camp (mean 196 ± SE 22 days). taxa and that the number of bird carcasses would increase Meetings with local chiefs were held to explain the purpose with the number of hunters using camps. Data were extra- of the study and seek permission to access camps before polated to all known hunting camps in the Ebo Forest to commencing fieldwork. Hunters in each village were em- estimate the minimum annual offtake for each species, and ployed as field assistants and porters, for a small fee. We here we discuss the potential effect of hunting pressure on used a global positioning system (GPS) to relocate camps birds in the forests of West and Central Africa. and map established trails.

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