Population characteristics of African wild dogs Lycaon pictus in the Eastern transvaal lowveld, South Africa, as revealed through photographic records

Biological Conservation 67 (1994) 57~i2

POPULATION CHARACTERISTICS OF AFRICAN WILD DOGS Lycaon pictus IN THE EASTERN TRANSVAAL LOWVELD, SOUTH AFRICA, AS REVEALED THROUGH PHOTOGRAPHIC RECORDS A. H. Maddock* & M. G. L. Mills National Parks Board, Private Bag X402, Skukuza 1350, South Africa

(Received 20 October 1992; revised version received 19 February 1993; accepted 28 February 1993)

have reduced a number of populations, as has been recently documented in the Serengeti ecosystem (Fuller & Kat, 1990; Fanshawe et al., 1991). The IUCN has classified the African wild dog as vulnerable, but it has been suggested that this be changed to endangered (Ginsberg & Macdonald, 1990), the status assigned to it in South Africa (Smithers, 1986). In South Africa, the Kruger National Park and surrounding private nature reserves in the Eastern Transvaal Lowveld is the only area where a viable population of African wild dogs exists. A small reintroduced population of possibly two packs numbering 30~5 animals occurs in the Umfolozi/Hluhluwe Game Reserve Complex in Natal, with an unknown number of small packs north and south of the protected area (Rowe-Rowe, 1992), and packs from Botswana occasionally enter the Kalahari Gemsbok National Park (Mills, 1990). Recently an attempt has been made to reestablish a small population in the northern Transvaal by the successful translocation of a pack from outside the Kruger National Park to the De Beers-Limpopo Venetia Private Nature Reserve (English et al., in press). Apart from the work of Frame et al. (1979) on the Serengeti plains no attempts have been made to count wild dogs outside the Kruger National Park, where two previous attempts were by Pienaar (1969), using game rangers' reports, and Reich (1981), who used radio tracking in combination with ranger and tourist reports. The latter study, however, was limited to the southern part of the park. In the present study we attempted to determine the population size and other demographic characteristics of wild dogs in the Kruger National Park and some of the surrounding privately owned conservation areas (Fig. 1). This was achieved through a novel method involving tourists, game rangers and scientists providing a photographic reference collection and other information.

Abstract Approximately 5,000 photographs of African wild dogs Lycaon pictus taken in the Kruger National Park and some neighbouring reserves, in combination with direct observations, were used to assess the number of dogs, their pack sizes, sex ratio and breeding success during 1988 and 1989. A total of 357 dogs were identified in 26 packs, giving a minimum density of 16.7 dogs/lO00 km 2. Comparisons with earlier observations suggest that this population has remained stable over the last 25 years. Mean pack size was 13.7 + SD 7.1 and the sex ratio of 1 male.'0.9 female close to parity. At least 69% of packs raised pups in 1988. Litter size at three months was 11.9 + SD 3.0 and pup mortality between four and 10 months was 44%. Pup survival was positively correlated with the number of females in a pack. This large conservation area with stable prey populations, and a low incidence of disease and poaching, provides an environment conducive to wild dog survival. Keywords: South Africa, African wild dogs, population INTRODUCTION

Historically the African wild dog or Cape hunting dog Lycaon pictus had a wide distribution throughout most of sub-Saharan Africa (Smithers, 1983, 1986). Recently their distribution and numbers have decreased drastically (Kingdon, 1977; Skead, 1980; Chides, 1988; Ginsberg & Macdonald, 1990; Hines, 1990). In a survey of 32 countries, Fanshawe et al. (1991) found that the species was extinct in 19, very rare in seven and present in low numbers in only six. The demise of the wild dog has principally been due to the increasing pressure from expanding human populations and agriculture, which has reduced the available habitat and the many wild bovid populations on which they feed (Smithers, 1983). Disease too may * Present address: Hluhluwe Game Reserve, PO Box 25, Matubatuba 3935, South Africa

STUDY AREA

Biological Conservation 0006-3207/93/$06.00 © 1993 Elsevier Science Publishers Ltd, England. Printed in Great Britain

The study was conducted in the Kruger National Park and neighbouring private nature reserves on its western 57

58

A. H. Maddock, M. G. L. Mills

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Fig. 1. The study area in the Eastern Transvaal Lowveld, South Africa. 1, Kruger National Park; 2, Sabie Sand Private Game Reserve; 3, Manyeleti Game Reserve; 4, Timbavati Private Game Reserve; 5, Klaserie Private Game Reserve. The dotted line indicates the approximate boundary between the western granite and eastern basalt soil types.

boundary (Fig. 1), an area of approximately 21 350 km 2. The region is underlain by basaltic and granitic basement rocks which strongly influence the vegetation communities. The eastern basaltic plains have an open savanna-type vegetation with Colophospermum mopane dominant in the north and Sclerocarya birrea and Acacia nigrescens dominating in the south. The western granitic soils support denser woodland communities with C. rnopane again dominant in the north and Combretum species in the south (Gertenbach, 1983). Impala Aepyceros melampus, the wild dog's main prey in this region (Reich, 1981), is common throughout, but more so in the woodland communities (Gertenbach, 1983). Annual rainfall ranges between 400 mm in the north and 800 mm in the southwest, although a localized area in the extreme northwest receives 700-800 mm per year (Gertenbach, 1980).

METHODS Each wild dog has a unique combination of black, white and tan markings (Frame et al., 1979; Smithers, 1983) which enables recognition of individuals. Photographic records have been found useful in identifying individual wild dogs in Serengeti (Frame et al., 1979; Malcolm & Marten, 1982) and formed the basis for the present study. The objective was to photograph every wild dog in the study area. Because of the low probability of locating wild dogs in this thick-bushed area, a large, widespread work force was needed. This was provided by the pool of approximately 600 000 annual tourists who visited the study area, field staff (game rangers and scientists) employed in the reserves and ourselves. The study area is covered by a comprehensive network of over

African wild dog in South Africa 12 10 ~8 t=

6

u. 4

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<5

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5-10

11-20

>20

Number of times photographed

Fig. 2. Frequency with which different wild dog packs were photographed. 3000 km of roads, along which the dogs often travel (Reich, 1981). Although an individual's chance of locating dogs on a given day are poor, the chances that somewhere somebody will do so are infinitely better. We assumed that tourists with adequate photographic equipment were evenly distributed throughout the total number of tourists and the study area. A competition run by the Endangered Wildlife Trust, with worthwhile prizes as incentives, encouraged the submission of photographs of wild dogs taken between January 1988 and June 1989. Information requested to accompany each set of photographs was date and time of sighting, locality (all roads in the Kruger National Park are numbered), and the number of adults and pups (animals approximately half adult size or less) seen.

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It soon became clear that the same dogs were always seen together, that these individuals occurred within a well-defined area, and that successive sightings of a particular group contained the same, or a similar number of, individuals. Such animals constituted a pack. Left- and right-side photographs of all individuals from each pack were pasted onto a large card and given a reference number. Field work, conducted from June 1988 to May 1989 by A.H.M., supplemented these observations. Attempts were made to locate all packs sighted by reacting to information provided by a network of helpers such as tourist officers, tour guides and field staff throughout the study area. Once a pack was located all individuals were photographed and detailed observations on sex and age were made. The population size of wild dogs in the study area was assessed by totalling our estimates of the number of dogs in each known pack on 1 January 1989. This date was chosen as the mid-year point in the breeding cycle of these seasonal breeders (Reich, t 981; personal observations). The number of times different packs were seen and photographed varied (Fig. 2), as did the size (Table 1) and the variation in successive counts, thus making some packs easier to count than others. For these reasons different criteria were used to estimate the sizes of the packs. These are summarised in Table 1. Sex ratios and age structure were determined by photographs or direct observations by A.H.M. The

Table 1. Pack size, criteria used for establishing the size of each pack, sex ratios and breeding records of African wild dogs in the Eastern Transvaal, 1988-1989

Pack

Size

Nsikazi Matjulwana Afsaal Crocodile Bridge Skukuza Doispane Pretoriuskop Mlondozi Kwa-Gamakhulu Mala Mala Sand River Nwanedzi Orpen Klaserie Phalaborwa Ngwenyeni Muthlumuvi Nkodozi Bububu Nkayeni Tshange Dzundwini Mahonie Mashikiri Matekevele Ramiti Orpen lone dog

5 6 15 16 22 10 10 21 11 3 8 19 30 22 21 20 23 5 11 21 7 12 9 12 12 5 1

Total

357

Criteria used

Five dogs photographed in December 1989 Two counts of six dogs in December 1988 and January 1989 Mean of five counts in January 1989 Two counts of 16 dogs in October 1988 and March 1989 Mean of six counts in December 1988 and January 1989 Mode of 10 counts in January 1989 Three counts of 10 between October 1988 and January 1989 Mean of three counts in December 1988 Mode of nine counts in December 1988 and January 1989 Two counts of three in October 1988 and January 1989 Seven counts of eight in December 1988 and January 1989 One count by ranger in February 1989 Three counts of 30 each in January and February 1989 22 dogs photographed in March 1989 Mean of four counts between December 1988 and February 1989 Two counts of 20 and 21 in November 1988 Mean of six counts December 1988 and January 1989 Two counts of five in December 1988 11 dogs photographed in February 1989 21 dogs photographed in March 1989 Three counts of seven dogs October 1988-March 1989 Three counts of 12 dogs February-April 1989 Three counts of nine dogs December 1988-January 1989 Two counts of 12 in January 1989 Two counts of 12 in January 1989 Photographed in January 1989 Photographed in February 1989

Sex ratio M:F

1:0.5 1:0.3 1 : 0-6 1 : 1.2 1: 1 1 : 1.3 -1:2 1 : 1.4 --1:0-9 1:4 1 : 0-4 1 : 0.6 1: 1 1: 1 -1 : 1.4 1 : 0-5 --1:0.9

Bred 1988 No No Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes No Yes Yes No No Yes Yes No No --

A. H. Maddock, M. G. L. Mills

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Table 2. Percentage of the total area of the Kruger National Park covered by three districts, road density, percentage of the wild dog sightings made by tourists, percentage of tourists overuighting in rest camps, and the number of packs identified in each region during 1988-1989

Region

South Central North

% of total area 19 29 52

Road % wild dog density sightings (km/km2) 1/5.7 1/7.6 1/10.9

% tourists No. of wild dog packs identified

48 29 23

67 19 14

7 5 14

large penile sheath of males makes it easier to sex these animals, even from some photographs and even when they are young. In the Eastern Transvaal Lowveld wild dogs almost always give birth during late May and June (Reich, 1981; personal observations). Lactating females can be determined by their swollen teats even several weeks after they have weaned their pups. Animals under ten months of age are considerably smaller than adults and can easily be classified as pups of that year. RESULTS Numbers During the study over 700 competition entry forms, each representing a sighting of a wild dog pack, and comprising nearly 5000 photographs, were received from visitors and field staff. In addition we made 25 pack sightings and contributed over 400 photographs. From these observations 26 packs and one lone dog were identified (Table 1), of which five were seen by tourists only. The remaining packs were seen at least once by ourselves (12), or other field staff (9). Wild dog sightings were unevenly distributed over the study area, due to the uneven tourist and road distribution (Table 2). Nevertheless, the number of packs identified in the three districts of the Kruger National Park (Fig. 1), did not differ significantly from the expected value, taking into account the relative sizes of the three districts and assuming packs were evenly distributed in each (X2 = 1.90; d.f. = 2; p > 0.05) (Table 2). Moreover, in the southern district, where intensive wild dog observations using radio transmitters have been conducted since January 1990 (Mills, in prep.), no additional packs than those accounted for during the present study were found. Overall 357 wild dogs were identified, which represents the minimum number present in the study area at Table 3. Three estimates of wild dog numbers in the Kruger National Park between 1964 and 1989

Region

1964 (Pienaar, 1969)

1978 (Reich, 1981)

1989 (Present study)

South Central North

100-120 65-80 150-160

70+

84 115 158

Total

315-360

357

Table 4. Adult pack size, litter size and pup survival between four and 10 months of African wild dogs in the Eastern Transvaal, 1988-1989

Pack

No. of adults

No. of pups

% survivors

At 3 months At 10 months Afsaal Crocodile Bridge Skukuza Doispane Pretoriuskop Kwa-Gamakhulu Orpen Ngwenyeni Muthlumuvi Total

9 5 10 5 5 7 15 20 11 87

13 12 13 10 13 7 16 8 15 107

8 6 9 5 3 4 13 4 8 60

62 50 69 50 23 57 81 50 53 56

the beginning of 1989. This gives a minimum density of 16-7 dogs/1000 km 2, or 1 dog/60 km 2. This is similar to Pienaar's (1969) estimate for the Kruger National Park, although regionally the two sets of data are less compatible (Table 3). Mean pack size was 13-7 + SD 7.1, which is higher than the median pack size of 11.2 calculated from a range of observations from different areas reported in Fuller et al. (1992). Only 1.2% of the sightings were of single animals, and only one of these animals could not be traced to a pack (Table 1). Sex ratios All the members of 16 packs were sexed either from direct observations or clear photographs. The sex ratio in these packs varied from a male:female ratio of 1:0-3 to 1:4. Seven packs showed a male bias, six a female bias and two parity, with the overall male: female ratio 1:0.9 (Table 1). This is not significantly different from parity (binomial test: P = Q -- 0.5; N = 225; x = 106; p -- 0.4562; two-tailed). In a smaller sample of six litters between three and four months of age, female pups tended to outnumber males (1 : 1.3), although this ratio did not differ significantly from parity (binomial test: P -- Q = 0.5; N = 53, x = 23; p -- 0.2061; two-tailed). Reproduction Eighteen (69%) of the 26 packs identified successfully raised pups past the three-month denning period in 1988 (Table 1). Litter sizes could not be determined until the pups left their natal den. The mean size of nine litters, from three to four months old, was 11.9 + SD 3.0 (Table 4). In each o f these packs only one lactating female was seen. The ratio of adults to pups seen between August and September 1988 was 1 : 1.2 (n = 194), but decreased to 1:0.7 (n = 1.47) by April 1989. The number of wild dogs, therefore, increased dramatically during the breeding season, but declined as a result of high juvenile mortality, which approached 440/0 between September 1988 and April 1989 (Table 4). Pup survival within the different packs varied (Table 4), but there was no correlation between pack size (n -- 9) and the number of surviving pups less than 10

African wild dog in South Africa months old (r2 = 0.106, p > 0.5). There was also no significant correlation between the number of surviving pups and the number of adult males in the pack (r2 = 0.001, p > 0.5), although there was with the number of adult females (r2 = 0.848, p < 0.05). However, because of the variation in sex ratio between packs, sex ratio was not correlated with pup survival. DISCUSSION This study used a new technique for gathering data on population size and other demographic parameters on a little-known and diffficulty-to-study endangered species, in an area where visibility is poor. Although most of the observations were made by untrained observers, photographic evidence was provided to substantiate them. This made it possible to identify individuals and packs from most sightings and often allowed a minimum count of pack members. In establishing pack size for each pack we used the best available counts (see Table 1). The fact that tourists and roads are not evenly distributed throughout the study area (Table 2) meant that certain packs were located often, whereas others were located infrequently (Fig. 2). In fact some packs may never have been located and some dispersing dogs may have been missed. In two ranger sections in the Kruger National Park rangers' reports suggested that there were more packs than had been recorded. Furthermore, packs have occasionally been reported as far as 30 km west of the boundaries of the study area. However, several factors point to most packs being recorded: (1) data were collected over an 18-month period during which a pack only had to be photographed once in order to be included in the population assessment, provided there was evidence that it was still present in the study area in January 1989; (2) wild dogs range over large areas (Reich, 1981; Gorman et al., 1992) and it is likely that all packs come into contact with tourist roads to a greater or lesser degree; (3) the number of packs recorded from the three districts of the Kruger National Park did not differ from the expected value, taking into account the relative sizes of the areas. We conclude, therefore, that the population estimate given here is the minimum, but the right order of magnitude, of the actual number in the study area. The minimum number of 357 wild dogs in the Eastern Transvaal Lowveld, which appears to have remained reasonably stable over the last 25 years (Table 3), is one of the few remaining viable and stable wild dog populations in Africa (Fanshawe et al., 1991; Fuller et al., 1992). The benefits of a large conservation area with stable populations of preferred prey, low incidence of disease and of poaching, provide an environment conducive to wild dog survival. This is borne out by the comparatively large pack size and obvious reproductive success of packs. Most wild dog studies have recorded a male bias in packs (Stevenson-Hamilton, 1947; Estes & Goddard, 1967; Pienaar, 1969; Schaller, 1972; Frame et al., 1979;

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Childes, 1988; Fuller et al., 1992). Malcom and Marten (1982) suggest that male helpers increase pup survivorship. However, neither Reich (1981) nor ourselves could find a male bias. Moreover, as far as pup survival, at least from four to ten months, is concerned, the number of females in the pack appeared to be more important than the number of males. Clearly these questions need more attention. Not only did this study yield important information on wild dog demography, it also accomplished an important public relations function. Because of the publicity the project enjoyed, it brought the plight of the African wild dog to public attention and may have helped to improve its tarnished image, factors important for its survival (Ginsberg & Macdonald, 1990; Fanshawe et al., 1991). ACKNOWLEDGEMENTS The National Parks Board, South Africa, the Endangered Wildlife Trust, Agfa Photographic Co., Photra Photographic Co. and Luxair are thanked for providing the financial backing for the study. We would also like to thank all those who took part in the photo competition, or otherwise provided information on dogs. We extend a special word of thanks to Jill Morrison and Caroline Maddock for their assistance and to Harry Biggs for commenting on an earlier draft of the manuscript. REFERENCES Childes, S. L. (1988). The past history, present status and distribution of the hunting dog Lycaon pictus in Zimbabwe. Biol. Conserv., 44, 301-16. English, R. A., Stalmans, M., Mills, M. G. L. & Van Wyk, A. (in press). Helicopter-assisted boma capture of African wild dogs. Koedoe. Estes, R. D. & Goddard, J. (1967). Prey selection and hunting behaviour of the African wild dog..I. Wild. Manage., 31, 52-69. Fanshawe, J. H., Frame, L. H. & Ginsberg, J. R. (1991). The wild dog--Africa's vanishing carnivore. Oryx, 25, 137-46. Frame, L. H., Malcolm, J. R., Frame, G. W. & van Lawick, H. (1979). Social organization of African wild dogs Lycaon pictus on the Serengeti plains, Tanzania 1967-1978. Z. Tierpsychol., 50, 255-49. Fuller, T. K. & Kat, P. W. (1990). Movements, activity, and prey relationships of African wild dogs Lycaon pictus near Aitong, southwestern Kenya. Afr. J. Ecol., 28, 330-50. Fuller, T. K. et al. (1992). Population dynamics of African wild dogs. In Wildlife 2001." Populations, ed. D. R. McCullough & R. H. Barret. Elsevier Applied Science, London & New York, pp. 1125-39. Gertenbach, W. P. D. (1980). Rainfall patterns in the Kruger National Park. Koedoe, 2,3, 3~44. Gertenbach, W. P. D. (1983). Landscapes of the Kruger National Park. Koedoe, 26, 9-121. Ginsberg, J. R. & Macdonald, D. W. (1990). Foxes, Wolves, Jackals and Dogs: An Action Plan for the Conservation of Canids. IUCN, Gland. Gorman, M. L., Mills, M. G. L. & French, J. (1992). Satellite tracking of the African wild dog Lycaon pictus. In Wildlife Telemetry: Remote Monitoring and Tracking of Animals, ed. I. G. Priede & S. M. Swift. Ellis Horwood, London, pp. 219-30.

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Hines, C. J. H. (1990). Past and present distribution and status of the wild dog Lycaon pictus in Namibia. Madoqua, 17, 31-6. Kingdon, J. (1977). East African Mammals: An Atlas of Evolution in Africa. Academic Press, London. Malcolm, J. R. & Marten, K. (1982). Natural selection and the communal rearing of pups in African wild dogs Lycaon pictus. Behav. Ecol. Sociobiol., 10, 1-13. Mills, M. G. L. (1990). Kalahari Hyenas: The Comparative Behavioural Ecology of Two Species. Unwin-Hyman, London. Pienaar, U. de V. (1969). Predator-prey relationships amongst the larger mammals of the Kruger National Park. Koedoe, 12, 108-76. Reich, A. (1981). The behavior and ecology of the African wild dog Lycaon pictus in the Kruger National Park. PhD thesis, Yale University, New Haven, Connecticut.

Rowe-Rowe, D. T. (1992). The Carnivores of Natal. Natal Parks Board, Pietermaritzburg. Schaller, G. B. (1972). The Serengeti Lion: A Study of Predator-Prey Relations. University of Chicago Press, Chicago, Illinois. Skead, C. J. (1980). Historical Mammal Incidence in the Cape Province. Department of Nature and Environmental Conservation of the Provincial Administration of the Cape of Good Hope, Cape Town. Smithers, R. H. N. (1983). The Mammals of the Southern African Subregion. University of Pretoria, Pretoria. Smithers, R. H. N. (1986). The South African Red Data

Book--Terrestrial Mammals. South African National Scientific Programmes Report, No 125. Pretoria. Stevenson-Hamilton, J. (1947). Wildlife in South Africa. Cassell and Co., London.