The Decline of an Urban Hooded Vulture Necrosyrtes Monachus Population in Dakar, Senegal, Over 50 Years

Ostrich Journal of African Ornithology

ISSN: 0030-6525 (Print) 1727-947X (Online) Journal homepage: http://www.tandfonline.com/loi/tost20

The decline of an urban Hooded Vulture Necrosyrtes monachus population in Dakar, Senegal, over 50 years

Wim C Mullié, François-Xavier Couzi, Moussa Sega Diop, Bram Piot, Theo Peters, Pierre A Reynaud & Jean-Marc Thiollay

To cite this article: Wim C Mullié, François-Xavier Couzi, Moussa Sega Diop, Bram Piot, Theo Peters, Pierre A Reynaud & Jean-Marc Thiollay (2017) The decline of an urban Hooded Vulture Necrosyrtes monachus population in Dakar, Senegal, over 50 years, Ostrich, 88:2, 131-138, DOI: 10.2989/00306525.2017.1333538 To link to this article: http://dx.doi.org/10.2989/00306525.2017.1333538

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Download by: [2.83.93.12] Date: 17 August 2017, At: 00:02 Ostrich 2017, 88(2): 131–138 Copyright © NISC (Pty) Ltd Printed in South Africa — All rights reserved OSTRICH ISSN 0030–6525 EISSN 1727-947X http://dx.doi.org/10.2989/00306525.2017.1333538

The decline of an urban Hooded Vulture Necrosyrtes monachus population in Dakar, Senegal, over 50 years§

Wim C Mullié1*, François-Xavier Couzi2, Moussa Sega Diop3, Bram Piot4, Theo Peters5, Pierre A Reynaud6 and Jean-Marc Thiollay7

1 BP 45590, 10700 Dakar-Fann, Senegal 2 Société d’Etudes Ornithologiques de la Réunion, Saint André, Île de la Réunion, France 3 AfriWet Consultants, Dakar-Thiaroye, Senegal 4 Cité Ndiatte Almadies, Ngor, Dakar, Senegal 5 Royal Netherlands Embassy, Dakar, Senegal 6 275 Rue Robert Schuman, 83000 Toulon, France 7 2 Rue de la Rivière, 10220 Rouilly Sacey, France * Corresponding author, email: [email protected]

As in many West African cities, in Dakar Hooded Vultures Necrosyrtes monachus have always been characteristic urban scavengers. The recent decline of Hooded Vultures in other parts of Africa, mainly eastern Africa, has been the reason in 2015 for up-listing of its status by the IUCN in the Red List of Threatened Species to Critically Endangered. As the Hooded Vulture is still common in the Lower Casamance, Senegal, in the Western Region of The Gambia and in Guinea-Bissau, without clear signs of a recent decrease, a survey of its current status in Dakar was undertaken and compared with historical data over the past 50 years. A strong decrease of >85% was noted from 3 000 individuals in 1969 to 400 in 2016. This decline is on the high end of the decline noticed over much of its range but in striking contrast with the apparently stable populations along the West African coast more to the south (The Gambia to Guinea). Likely causes are (1) exponential urbanisation resulting in loss of feeding sites and reduced food availability, (2) increased poisoning of feral dogs with strychnine sulphate due to an upsurge of rabies and (3) increased disappearance of suitable trees for nesting and roosting.

Déclin d’une population urbaine des Vautours charognards Necrosyrtes monachus sur 50 ans à Dakar, Sénégal

A Dakar, comme dans de nombreux centres urbains de l’Afrique de l’Ouest, les Vautours Charognards Necrosyrtes monachus ont toujours été des charognards caractéristiques de ces villes. Le récent déclin des Vautours Charognards dans d’autres parties de l’Afrique, principalement en Afrique de l’Est, a motivé, en 2015, son inscription sur la Liste rouge de l’UICN comme espèce menacée «En danger critique d’extinction». Cependant le Vautour Charognard est encore commun en Basse Casamance (Sénégal), dans la partie occidentale de la Gambie et en

Downloaded by [2.83.93.12] at 00:02 17 August 2017 Guinée-Bissau sans indicateurs d’un déclin de sa population. Ainsi une enquête sur son statut actuel à Dakar a été menée afin d’effectuer une comparaison avec les données disponibles des 50 dernières années. Une forte baisse (>85%) a été notée de 3 000 individus en 1969 à 400 en 2016. Ce déclin correspond aux chutes des populations ailleurs en Afrique mais contraste avec les populations apparemment stables de la Gambie à la Guinée. Les causes probables de déclin sont (1) une urbanisation galopante entraînant une perte de sites d’alimentation et une réduction de la disponibilité de nourriture, (2) une intoxication accrue de chiens sauvages avec du sulfate de strychnine due à une recrudescence de la rage et (3) une disparition accrue des arbres appropriés pour la nidification et le repos.

Keywords: cutting of trees, Hooded Vulture, Necrosyrtes monachus, poisoning, population estimate, slaughterhouse sanitation, urban development

Online supplementary material: Supplementary information for this article is available at http://dx.doi.org/10.2989/00306525.2017.1333538

Introduction

Large declines in Hooded Vulture Necrosyrtes monachus up-listed to the status of Critically Endangered (CR) in across its African range were reported by Ogada and 2015 on the IUCN Red List of Threatened Species (BirdLife Buij (2011) and Ogada et al. (2016) and the species was International 2016). Only recently did it become clear that

§ This article is part of a special issue on vultures in memory of André Boshoff

Ostrich is co-published by NISC (Pty) Ltd and Informa UK Limited (trading as Taylor & Francis Group) 132 Mullié, Couzi, Diop, Piot, Peters, Reynaud and Thiollay

in a restricted area in West Africa Hooded Vultures are still Apart from the above-mentioned situation in the Depart- occurring in high densities and their populations might have ment of Ziguinchor (Casamance), the Hooded Vulture suffered less than those from other areas within their range. situation in other parts of Senegal has received little This is the case in the Western Region of The Gambia attention. During a four-day trip in the western part of (Jallow et al. 2016) where 3 416 individuals were counted Senegal covering some 2 700 km in October 2016, a total on road transects; the Ziguinchor Department of south- of 581 Hooded Vultures were observed on road transects western Senegal where 2 350–2 700 pairs were estimated (data courtesy ARDB) or 21.5 individuals per 100 km, which by Bruno Bargain (in BirdLife International 2016) and is low compared with 252 individuals per 100 km in Guinea- particularly in Guinea-Bissau where the total population was Bissau (Henriques et al. 2017) and 1 750 individuals per estimated to be 76 000 individuals based on transect counts 100 km in The Gambia (Jallow et al. 2016). Jean Delannoy (Henriques 2016) of which >7 000 occurred in the town of (pers. comm.) estimated that in the town of Tambacounda Bissau. In West Africa Hooded Vultures are mainly found in eastern Senegal during the rainy season some 100–200 close to human habitations where they exploit slaughter- Hooded Vultures are present. The current paper documents houses, market places and rubbish dumps (Mundy et al. the known, albeit scattered, information on the urban 1992; Ogada and Buij 2011). They breed and feed here in Hooded Vulture population in Dakar, Senegal, since 1969. the same areas close to humans, which is not necessarily the case in East Africa (Odino et al. 2014) or, more Materials and methods generally, south of the Equator where they reportedly avoid close contact with humans (Mundy et al. 1992). A first estimate of the number of Hooded Vultures was In the mid-1990s, Jean-Marc Thiollay (pers. obs.) already made on 14 January 1969, 28 July and 22 August 1971 by noticed spectacular and hitherto unexplained declines, J-M Thiollay. Numbers roosting in trees, mostly within and if not complete extinctions, in several West African towns near the main Muslim cemetery at Soumbedioune along the compared with the late 1960s. This was the case, among Corniche West as well as along the main avenues in Dakar, others, in Niamey (Niger), Bouaké (Ivory Coast) and were estimated but not counted. The whole urban area was Bobo-Dioulasso (Burkina Faso). Meanwhile, numbers in not covered at that time. Ouagadougou (Burkina Faso) have also sharply decreased In 1997–1998 a quantitative study of urban scavengers (BO Diallo 2010; Weesie in Ogada and Buij 2011). in Dakar was conducted by Couzi (1998) with Hooded

MAURITANIA a

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ladies or

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INIAN OCEAN Daar

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Figure 1: Morning (a) and afternoon (b) densities (individuals km−2) of Hooded Vultures on counting units in 1997 in neighbourhoods of the Dakar peninsula, Senegal. The counting units with a + sign were not visited in 2016 Ostrich 2017, 88(2): 131–138 133

Vultures, Cattle Egrets Bubulcus ibis, Yellow-billed Kites the area that had been covered by Couzi (1998), with Milvus parasitus and Pied Crows Corvus albus being the exception of the units indicated by the symbol ‘+’ in the targeted species. The study area was divided into Figure 1a, which were not visited. Ngor Diarama and Yoff 40 neighbourhoods, subdivided into 219 counting units, one Tonghor roosts (Figure 2) were only counted from sunrise to six per neighbourhood (Figure 1). In each unit, both during until 3 h thereafter. Counts on all other roosts were either in the wet season (June–September 1997) and the dry season the morning or started generally 1.5–2 h before sunset and (October 1997–March 1998), two counts were made. These continued until 15–30 min thereafter. During evening counts, counts were on a single day: 07:30–10:30 and 16:30–19:30, birds already present were counted and those arriving were and all Hooded Vultures present were counted (perched, added. On morning counts, birds leaving were counted and feeding and flying), detected by eye during 20 min. the individuals remaining in the roost at the end of the count During 2016, on 15–19 June (end of the dry season), were added. All counts were made by two observers with 15–30 August (early rainy season) and 16–24 September the exception of Cité SAR, Almadies-Yoff and Tonghor, (end of the rainy season), we counted Hooded Vultures which were counted by a single observer. For each roost the sitting in, or flying near, roosts. Only total numbers were activity of the Hooded Vultures (perched, flying and feeding) counted without making a distinction between age classes. and the type of perch (tree and species, and man-made Hooded Vultures were counted during both morning (N = 20) structures such as antennas, buildings and street lights) and evening visits (N = 19) in the three periods (Table 1). were recorded. After the three counts had been completed, Roosts had been selected based on previous knowledge a new important roost was discovered on 28 November or were discovered during reconnaissance searches. The 2016. It was situated at the main slaughterhouse and was area of Dakar that was searched for roosts was similar to invisible from public roads. The methodology for assessing numbers of Hooded Vultures present in Dakar, which was applied in each of Table 1: Number of daily counting periods of Hooded Vultures on the three distinct time periods, is different. We consider roosts in Dakar during 2017 during the dry (June) and rainy (August and September) seasons. A few incidental observations were the 1969–1971 and 2016 methodology as being the most used to supplement roost counts. RC = roost count, IO = incidental similar, allowing for a direct comparison of total numbers. observation Results Month Type Morning Evening Total June RC 1 8 9 1969–1971 IO 1 0 1 The total estimate for the roosting sites visited in 1969 and August RC 6 3 9 1971 was 3 000 birds. The numbers should be considered IO 4 0 4 as a minimum and they did not seem to have markedly September RC 6 7 13 changed between the two years and seasons. IO 0 1 1 Total 18 19 37 Downloaded by [2.83.93.12] at 00:02 17 August 2017

Osrti sits tr sri iistrti ris ct Othr trs i i Building trt iht str

Figure 2: Distribution and number of Hooded Vulture roosting sites in 2016. The pie charts show activities and characteristics of perches. The size of the pies is proportional to the number of vultures counted (Table 3; also for roost codes). The later discovered roost at the slaughter house is not indicated on this map, but see text 134 Mullié, Couzi, Diop, Piot, Peters, Reynaud and Thiollay

Table 2: Counts of Hooded Vultures (number of individuals) in Dakar neighbourhoods in 1997–1998 during the rainy and dry seasons (summarised from Couzi 1998). Numbers of birds given are for all activities combined, i.e. flying, roosting and feeding. The surface areas of individual neighbourhoods are also given

Counting Surface Rainy Dry Counting Surface Rainy Dry No. Neigbourhood No. Neigbourhood units (ha) season season units (ha) season season 1 Anse Bernard 1–6 13.55 8 1 21 Les Almadies 101–106 16.49 1 1 2 Anse des Madeleines 7–12 4.12 1 1 22 Complexe King Fahd 107–111 5.89 2 0 3 Plateau 13–16 30.63 2 4 23 Ngor village 112–117 4.71 0 1 4 Centre Ville 17–22 13.55 5 0 24 Warar 118–123 9.42 5 0 5 Grande Mosquée 23–27 14.73 4 5 25 Yoff village 124–129 62.43 0 0 6 Port et Zone industrielle 28–33 43 56 10 26 Ndoup zone agricole 130–135 77.16 6 14 7 Médina geule Tapée 34–39 19.44 3 0 27 Bel-Air Hann Plage 136–141 31.81 13 7 8 Cimetière Soumbédioun 40 25.33 0 0 28 Hann Pêcheurs 142–147 84.23 79 26 9 Université UCAD 41–46 37.7 45 0 29 Park Hann 148–152 14.14 40 71 10 Fann-Résidence 47 31.81 2 0 30 Collège Mariste 153–158 9.42 9 1 11 Kolobane 48–53 38.29 2 0 31 CTO 159–164 25.92 37 16 12 Obélisque 54–58 2.36 0 0 32 Grand Yoff 165–170 28.27 5 7 13 Grand Dakar 59–64 83.64 7 0 33 Niayes Patte d’oie 171–176 14.73 18 0 14 Point E 65–69 26.51 0 0 34 Parcelles assainies 177–182 56.54 0 0 15 Karak 70–75 5.89 1 0 35 Golf Cambérène 183–188 6.48 0 1 16 Fenètre Mermoz 76–81 14.73 2 0 36 Centre Int. d’échanges 189–194 97.77 8 0 17 Gouye Sor 82–87 25.33 3 0 37 Dunes Hann 195–200 6.48 20 10 18 Les Mamelles 88–92 67.74 0 0 38 Ndounge Dargou 201–206 11.78 6 9 19 Ouakam 93–98 27.68 0 0 39 Guenou Mbaw 207–212 55.96 4 7 20 Aéroport 99–100 412.89 0 0 40 Dagoudane Pikine 213–219 34.16 14 4 Total 1 592.71 408 196

1997–1998 Birds used various structures to roost (Table 3, Figure 2). Total numbers counted were respectively 196 in the dry Trees were widely used (84%, N = 282) and only at smaller season and 408 in the rainy season (Table 2). The total roosts did birds use man-made structures (5%, N = 16). maximum estimate for the whole period was 500 birds, It cannot be excluded that in a few cases the latter were which was in the rainy season. only pre-roosts. The remainder of the birds were either The spatial distribution of the birds is given in Figure 1. flying (7%, N = 22) or feeding (4%, N = 15). Of the trees, casuarinas (Casuarina equisetifolia) were the most used 2016 (66%, N = 186), followed by coconut palms (Cocos nucifera; During the 2016 roost counts there was also a marked 28%, N = 79) whereas only in the Parc de Hann, a zoo and difference between late dry season (234 individuals) and botanical garden/recreational park, were other trees, such early rainy season (335 individuals) (Table 3; raw data in as baobab Adansonia digitata and eucalypts Eucalyptus Supplementary Appendix S1). The visit to the slaughter- spp., used to roost (6%, N = 17). Downloaded by [2.83.93.12] at 00:02 17 August 2017 house on 28 November 2016 recorded c. 50 birds, feeding With the exception of Technopole, all roosts were in a on remains of carcasses and intestines. According to narrow coastal band within 600 m from the seashore employees of the slaughterhouse, all slept in Casuarina (Figure 2). Arrival and departure times on roosts depended equisetifolia trees elsewhere on the site and were also on the weather, with birds leaving later in the morning present during our previous counts (ML Ndiaye pers. when it was overcast. Most birds entered the roost within comm.). Birds roosting in June in the periphery of the 1 h before dusk, but here also it varied with some birds harbour were associated with nests. A total of nine already present at least 2 h before dusk (University vultures was associated with five (empty) nests (nos 7–10 Cheikh Anta Diop; UCAD) or staying all day and feeding in Figure 2). During the later counts, birds were not seen or roosting on site (zoo). Donkeys were slaughtered three again near these nests but aggregated in one or more times a week in the zoo. Birds that had been feeding on groups. In August, the two birds seen at Technopole (no. 15 their remains tended to stay until very late in their roost the in Figure 2) were also seen near a nest. On this nest a next day. Within each counting period, the weather was chick had been raised during the preceding dry season and fairly stable and typical for the season (Supplementary it was again occupied in April–May 2017. Total numbers Appendix S2). seen in any of the three months likely were incomplete for the following reasons: (1) more birds may have roosted Discussion near other nests, which were not systematically searched for; (2) other roosts may have been present but were not Population trends and seasonality found; and (3) more vultures were present on roosts but Based on roost counts in Dakar, numbers have dropped were not seen because they were hidden in dense foliage. from approximately 3 000 in 1969–1971 to 400 in 2016. Therefore, we estimate the early rainy season population of In 1997 total numbers were estimated to be at least Hooded Vultures in Dakar to be at least 400 individuals. 500, but as the methodology applied was not similar, a Ostrich 2017, 88(2): 131–138 135

Table 3: Counts of Hooded Vultures (number of individuals) on roosts in Dakar in June (late dry season), August (early wet season) and September (late wet season) 2016. Details of the substrate used and the activity of the birds are only given for the early wet season count, which produced the highest numbers of Hooded Vultures. Results from the two other counts show the fluctuations of Hooded Vulture numbers on roosts. NC = not counted

Trees Man-made structures Active Total Early Late Code Date Site Casuarina Cocos Other Street Fuel Late dry Building Feeding Flying rainy rainy equisetifolia nucifraga trees light storage season season season See text Slaughterhouse1 50 0 0 0 0 0 0 0 50 50 50 1 21-8-2016 Yoff Tonghor 0 9 0 0 0 0 0 0 9 2 NC 2 17-8-2016 Ngor Diarama 0 12 0 0 0 0 0 0 12 15 4 3 30-8-2016 Almadies, Mouth 0 0 0 2 0 0 0 0 2 2 6 Canal Ngor 4 30-8-2016 Almadies, King Fahd 0 0 0 2 0 0 0 0 2 2 0 5 31-8-2016 Ouakam, monument 0 0 0 0 2 0 0 0 2 3 4 6 15-8-2016 UCAD 60 42 0 6 0 0 0 0 108 60 76 7 18-8-2016 Harbour WP 504 0 0 0 0 0 0 0 3 3 2 0 8 18-8-2016 Harbour WP419 0 0 0 0 0 0 0 2 2 2 13 9 18-8-2016 Harbour WP 505 0 0 0 0 0 0 0 5 5 3 0 10 18-8-2016 Harbour WP 418 0 0 0 0 0 0 0 3 3 3 0 11 27-8-2016 Hann Marina 6 0 0 0 0 2 0 1 9 11 19 12 27-8-2016 Hann, Cercle Etrier 6 0 0 0 0 0 0 0 6 2 0 13 20-8-2016 Parc de Hann + Zoo 25 11 17 0 0 0 15 8 76 42 22 14 28-8-2016 Pikine 0 0 0 0 2 0 0 0 2 NC NC 15 15-8-2016 Technopole 0 2 0 0 0 0 0 0 2 0 0 16 17-8-2016 Cité SAR 39 3 0 0 0 0 0 0 42 35 50 Downtown Dakar NC NC NC NC NC NC NC NC NC NC 11 Total 186 79 17 10 4 2 15 22 335 234 255 Proportion 0.56 0.24 0.05 0.03 0.01 0.01 0.04 0.07 1 1 Based on information obtained at the slaughterhouse on 28 November 2016, it is likely that approximately 50 individuals were present at the time of each of our previous counts

direct comparison is not appropriate and it is likely that significantly to declines’. Similar findings came from South true numbers were much higher. Nevertheless, the total Africa where McKean et al. (2013) collected evidence to decrease over almost half a century is >85% and this suggest that traditional use was at least partly responsible decline did not start recently, as is the case in many sites for the rapid decline of vulture populations in that country. throughout the African continent (Ogada et al. 2016). Another factor that is frequently mentioned as During the 1997 study, numbers counted during the contributing to the rapid decline, particularly in East Africa, rainy season were higher than during the dry season. is the intentional use of carbamate pesticides to poison This was also the case in 2016, but with only three carcasses of livestock by herders to kill predators and Downloaded by [2.83.93.12] at 00:02 17 August 2017 surveys done it cannot be reliably assessed if the higher carcasses of elephants by poachers, most notably Furadan numbers are caused by seasonal migration or the simple (carbofuran) (Otieno et al. 2010; Roxburgh and McDougall result of redistribution of birds that were missed during 2012; Ogada et al. 2012, 2015; BirdLife International the dry-season count, which corresponds to the breeding 2016). The latter type of poisoning is used intentionally season of the species. Higher numbers during the rainy to kill vultures as a means to avoid attracting attention season were also mentioned to us from Tambacounda to carcasses left behind by the poachers. Poisoning is (J Delannoy, pers. comm.), but in The Gambia analysis widespread throughout Africa. In the pastoral areas of of data collected from satellite-tagged individuals did not northern Senegal and southern Mauritania vultures have reveal such seasonal differences in occurrence (K Bildstein, severely declined in recent decades (WCM pers. obs.). pers. comm.). The possibility of seasonal migration of the This was mainly due to the systematic use of strychnine Hooded Vulture on the south–north axis of Senegambia– to kill predators of livestock (Touré 1990). A recent case Mauritania was previously discussed by Thiollay (1977), of poisoning of a cow carcass was discovered in early without mentioning the Dakar area specifically. December 2015 by Jean Delannoy (pers. comm.) in the Réserve Naturelle Communautaire du Boundou, near General factors contributing to population decline Goudiry, eastern Senegal. Of a total of 35 dead birds The rapid decrease of Hooded Vulture populations in discovered, 27 were Hooded Vultures. Although material West Africa is attributed to a number of factors. Off-take for residue analysis was lost, the rapid death makes it likely of Hooded Vultures per annum for fetish and bush meat the poison used was a carbamate. in West Africa was estimated by Buij et al. (2016) to be The veterinary use of non-steroidal anti-inflammatory 975–1 462 individuals. The authors further state (p. 606) drugs, most notably Diclofenac, which was responsible for that this ‘represents a sizeable proportion of regional the massive declines of vultures in Asia (e.g. Green et al. populations, suggesting that trade is likely to be contributing 2004), is probably not yet a major concern in Africa, but 136 Mullié, Couzi, Diop, Piot, Peters, Reynaud and Thiollay

this threat still lacks detailed studies (Anderson et al. 2005; Hooded Vultures are currently concentrated and which still Woodford et al. 2008). have many suitable trees. In fact, a road count from Dakar Improvements in abattoir hygiene and rubbish disposal to Thies in 1969 produced 2 400 individuals (JMT pers. have also been attributed to the continent-wide declines obs.). This was repeated on 22 October 2016 when only of Hooded Vultures (Ogada and Buij 2011). Extinctions six individuals were observed. It appears, therefore, that the recorded in large towns in West Africa also appear to have decrease of Hooded Vultures in these suburbs was even followed the construction of large, modern and well-closed more dramatic than in the city of Dakar, making a simple slaughterhouses leaving fewer left-overs for vultures. shift of Hooded Vultures to the eastern suburbs unlikely. When comparing the distribution of roosting/feeding in Causes of decline in Dakar 1997 (Figure 1) with the roosting in 2016 (Figure 2) we see Increase in built-up areas and reduction of open space/ similarities and differences. In 1997, Hooded Vultures were cutting of trees still present in good numbers in the neighbourhoods of Yoff, Dakar is built on a peninsula and therefore can only Camberene, Hann, Mbao and Pikine (corresponding with increase either in density and/or height of buildings or units 30–40 in Table 1). Meanwhile, these areas have been by encroachment of the landside (eastern part) of the built up. The similarity is along the coasts where Hooded peninsula. Indeed, these factors act simultaneously Vultures were concentrated in both periods. This is probably and very rapidly. In 1970 Dakar had less than 700 000 because these are the oldest built-up areas and therefore inhabitants (ANSD 2009) and thus it was much smaller and still have more and taller trees. A comparison between less dense than in 2013 when the population had increased morning and afternoon distribution (Figure 1) suggests to 3.1 million inhabitants (ANSD 2016). that birds stay in the same neighbourhood for feeding and The exponential increase of built-up areas in Dakar roosting. Also in 2016, birds did not seem to undertake and its surroundings will continue. The urbanisation of the long-distance flights to and from roosts: within a radius of Senegalese population is expected to be 56% in 2021 and 2–3 km from the UCAD roost, there were always dozens the major part of this urban population will be concentrated of Hooded Vultures during the day. Without telemetry or in the greater Dakar area (Diallo 2007). marking birds, this can for the moment not be elucidated The rapid increase in built-up areas and reduction of open with certainty. space in Dakar goes hand-in-hand with an unprecedented cutting of large and suitable trees (Sudonline 2010; Sané Poisoning and direct persecution 2014), which are used by Hooded Vultures both for roosting Poisoning of Hooded Vultures in Dakar may largely go and breeding. Hooded Vultures in Dakar have a preference unnoticed. An upsurge of rabies since 2009 in Senegal for casuarinas and to a lesser extent coconut palm trees led to the establishment of a programme to reduce the for roosting. Other trees are rarely used, which is likely due feral dog population by the use of meat soaked in a to their scarcity. Only in the Hann botanical garden and at strychnine sulphate solution. Poisoned bait is placed where the zoo do Hooded Vultures also roost in other trees. In stray dogs concentrate, such as land-fill sites, beaches, particular, the casuarinas along roads are under strong cemeteries, barracks, hospitals, markets and slaughter- pressure and they have largely disappeared from some houses (PMD Diallo 2010). Between 2011 and 2016, avenues, such as around the harbour and the Bay of Hann, 21 329 stray dogs were eliminated nationwide (Anon. and this may be an additional factor in the reduction of 2016), raising serious questions about the potential impact Hooded Vulture numbers. The cutting of trees that are used on vultures. Strychnine is known to be very highly toxic (oral

Downloaded by [2.83.93.12] at 00:02 17 August 2017 −1 either for nesting or roosting has been mentioned by various LD50 < 5 mg kg ) on an acute basis to a number of bird authors in other regions on the continent as a likely cause species, such as chicken Gallus gallus domesticus, Mallard of Hooded Vulture decline (Ssemmanda and Pomeroy Anas platyrhynchos, Feral Pigeon Columba livia, House 2010; Roberts 2013). Interestingly, B. Bargain (in BirdLife Sparrow Passer domesticus and Common Starling Sturnus International 2016) also mentions a decline in the number of vulgaris (McLeod and Saunders 2013 and references the Hooded Vultures’ favourite nesting tree species (Ceiba therein). Incidentally, Hooded Vultures have been found pentandra) in Casamance as a potential threat. Large-scale poisoned at the Dakar University campus roost after stray cutting of mature trees in towns is likely to have a larger dogs had been poisoned. Two such cases were reported impact where trees are already scarce, such as in Dakar. in August 2016 by a local employee at the campus, and A recent study confirms that the environment of the these may represent the tip of the iceberg rather than greater Dakar area is rapidly deteriorating with a decrease just being occasional incidents. According to Odino et in green areas, farmlands and wetlands and an increase in al. (2014), little information on the scale of stray dog air, water and soil pollution (JICA 2016). One could argue poisoning in Africa is available and the impact on vultures that the Hooded Vultures that were driven out of the areas is likely underestimated. Vulture declines in Asia have that became less attractive, settled in the new neighbour- been found to lead to a dramatic increase in feral dogs and hoods to the east. However, large numbers of Hooded a subsequent increase in rabies (Markandya et al. 2008; Vultures were not recorded in visits to these areas. These Ogada et al. 2012). If the upsurge of rabies in Senegal is newly developed neighbourhoods, often constructed without linked to vulture decline remains an unanswered question. any urban planning (JICA 2016), typically lack mature Direct persecution of Hooded Vultures appears to be trees, as existent trees are often cut to make space for uncommon. In 2016 we were informed by the owner of a construction. Therefore, these are very different from the large hotel complex that he blamed the Hooded Vultures old neighbourhoods of Dakar bordering the coast where the to have caused the death of some of the coconut palms in Ostrich 2017, 88(2): 131–138 137

which they slept. He therefore deliberately destroyed an Use as fetish/traditional medicine occupied nest elsewhere on the complex. Such cases are The use of vulture parts for fetish/traditional medicine is probably rare. also known to occur in Dakar, although items might not be very numerous and even their origin is not clear as many Availability of food traders come from abroad. The number of street vendors Although the rubbish disposal system of Dakar has of fetishes in Dakar was estimated to be 130–150 (Bishop improved over the years, the rapid population growth and and Garzon 2003). In 2016, the Faunal Department of the problems with disposal in some neighbourhoods during the Waters and Forests Directorate (DEFCS) in collabora- rainy season, or even complete absence of such services in tion with the Directorate of Criminal Investigations (DIC) others, provides potentially enough food for the remaining confiscated animals and animal parts for sale (Capt. Hooded Vulture population. Nevertheless, Hooded Vultures A Sonko, pers. comm.). The origins of the confiscated in Dakar do not seem to exploit these resources if they are material, also containing parts of Hooded Vultures, was too close to houses. This is rather surprising, as e.g. in from a wide geographical area, not limited to Dakar or even Bissau (Guinea-Bissau) and Conakry (Guinea) Hooded Senegal. Despite the uncertainty about their origins, there Vultures are freely mixing with humans around small is definitely a demand for Hooded Vulture parts. Along rubbish heaps on street corners and beaches or waiting the so-called Petite Côte, immediately south of Dakar, at local street restaurants to get their share from chicken according to Reynaud (2007) Hooded Vulture parts are bones and similar remains (Henriques 2016; BP pers. obs. used either as a remedy against certain illnesses, such 2016). They do, however, avoid the central land-fill site of as leprosy (Bambara), stomach aches, sore kidneys, Bissau because this is frequently being burnt (M Henriques, and ecto- and endoparasites (Bambara), or as charms to pers. comm.). In Ziguinchor, Casamance, Hooded Vultures become invulnerable (Serere), pass an examination and/or also mainly frequent discharges of rubbish situated in the be appointed to a position of responsibility, or to see one’s town’s periphery (B. Bargain, pers. comm.). future (Wolof and Serere) (known ethnic groups in italics). Beaches in Dakar are now extensively being used for recreational purposes and Hooded Vultures are rarely Conclusion encountered. During 11 special missions along the beach from Dakar to Saint-Louis (170 km) since 2014, for the In summary, from the available information we deduce that surveillance of marine vertebrate strandings (Mullié et al. the driving force for the >85% reduction in the population of 2014), a single Hooded Vulture was seen (WCM pers. obs.). urban Hooded Vultures in Dakar is likely a combination of However, in The Gambia Hooded Vultures are frequently three factors: seen on beaches where they also feed on carcasses (1) the exponential increase in built-up areas and densities of cetaceans. In the Casamance, Hooded Vultures are of habitations causing the reduction or complete frequently seen on beaches feeding on stranded fish (WCM disappearance of open feeding areas and food sources pers. obs., March 2016; BP pers. obs., October 2016 and and the sanitation of the main slaughterhouse March 2017). Thus, it appears that feeding behaviour varies (2) the continued and wide-scale use of strychnine over even rather short distances, as Banjul (The Gambia) is sulphate to eradicate feral dogs only 170 km from Dakar and Bissau 370 km. Within Dakar (3) the major reduction of suitable trees for roosting and itself we noticed differences in behaviour, as at the main nesting. slaughterhouse of Dakar and at the slaughtering unit of Given the status as Critically Endangered and the Downloaded by [2.83.93.12] at 00:02 17 August 2017 donkeys at the zoo in the Hann park, Hooded Vultures are ongoing population decline of Hooded Vultures on the rather tame and approachable. The discharges of carcasses Dakar peninsula, there is a pressing need to answer at the zoo and the slaughterhouse are not open to the questions such as why populations are seemingly stable in general public. It is plausible that the Hooded Vultures adapt the south (The Gambia to Guinea) and decline to the north readily to local differences in the attitude of people towards of these. Such information should be used in conserva- them. Behavioural plasticity is an important trait of birds living tion action to prevent further decline and restoration of the commensally with humans (Murgui and Hedblom 2017). remnant Hooded Vulture population north of The Gambia. Although the Dakar slaughterhouse is still an important feeding site for Hooded Vultures, this is likely to change. A Acknowledgements — We are grateful to Capt. Abba Sonko, methane digesting pilot plant is already operational, using Departement de la Faune, Direction des Eaux et Forets, Chasses blood and undigested contents of the digestive tracts of et de la Conservation des Sols for providing the necessary permits slaughtered livestock. A large full-scale methane digestion to access the restricted zones in the Hann Zoo, to Dr Mouhamadou L Ndiaye, Thecogas Senegal, for allowing access to the facility, which will eliminate the majority of digestible Slaughter house and Biogas facility, and to Mr Joost van Dieren, left-overs, will be constructed. The non-usable remains will Ms Josephine Frantzen, Mr Antonio Araujo, Mr Jean Delannoye be stored in closed containers before disposal to the main and Mr Bruno Bargain for providing information or help with counts. rubbish dump facility, which would leave nothing for the The comments of two anonymous referees were very helpful to vultures. Fortunately, the company was open to our sugges- improve the manuscript. tions to make adaptations to the plans in order to keep edible remains available for the vultures. 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Received 14 January 2017, revised 16 May 2017, accepted 17 May 2017 Associate Editor: Campbell Murn