Migration of a Peregrine Falcon Falco peregrinus calidus from Saudi Arabia to Cape Town as revealed by satellite telemetry

In boreal autumn 1995, we tracked a migrating adult Peregrine Falcon Falco peregrinus calidus from the border of Saudi Arabia and Yemen to near Cape Town, South Africa, a distance of 6 346?km. While on migration it covered 288?km d?1, on average. During its migration in Africa it migrated faster than any other Peregrine tracked so far using satellite telemetry. Falco p. calidus is an uncommon, but regular, migrant to southern Africa, where it overlaps with the resident F. p. minor, but no other bird has been tracked so far south.     

ORGANOCHLORINE RESIDUES AND EGGSHELL THINNING IN THE PEREGRINE FALCON FALCO PEREGRINUS MINOR IN ZIMBABWE

Hartley, R.R., Newton, I., & Robertson, M. 1995. Organochlorine residues and eggshell thinning in the Peregrine Falcon Falco peregrinus minor in Zimbabwe. Ostrich 66: 69–73.

Several types of organochlorine residues were found in eggs of Peregrine Falcons Falco peregrinus minor taken in Zimbabwe in 1990. DDE (range = 0.2–22 ppm wet weight; geometric mean 1.8 ppm) was found in all eggs (n = 15) from 13 sites, including two pars in captivity. Eggs from two sites in the mid-Zambezi Valley, the most recently and heavily sprayed areas (5–8 times for tsetse fly Glossina sp. control), had the highest levels, one beyond that regarded as critical for successful reproduction. Mean shell thickness (Ratcliffe index) of the 1990 eggs was 10% (range = 2–29%) lower than the presumed pre-DDT mean. HEOD was detected in two eggs, HCB in one egg, and PCBs in all eggs, but at levels too low to affect breeding performance. Young were fledged from each of 12 sampled sites, yielding 1.86 young per site.     

Factors affecting breeding success of Peregrine and Lanner Falcons in South Africa

Jenkins, A.R. 2000. Factors affecting breeding success of Peregrine and Lonner Falcons in South Africa. Ostrich 71 (384): 385-392. Breeding success was recorded for three Peregrine Falcon, Falco peregrinus, populations in South Africa over nine years, and for Peregrine and Lanner Falcon, Ebiarmicus, populations in an area of sympatry over three years. The objectives of the study were to measure geographic and interspecific variation in reproductive performance, and determine environmental correlates of productivity. Territory occupancy, the frequency of breeding per occupied territory and clutch size did not vary significantly between the three Peregrine populations. However, Peregrine breeding success was generally lower on the Cape Peninsula (1. 11 young fledged per territorial poir), higher in the Soutpansberg (1.36) and highest on the Orange River (1.70). Overall, fledging rates of Soutpansberg Peregrines and Lanners were not significantly different, although annual productivity of the Lonner population was consistently higher. Neither species' breeding success was significantly depressed by the presence of close neighbouring pairs of the other, suggesting that they were not active competitors. Breeding performance of Peregrines on the Cape Peninsula correlated strongly with spring weather conditions: egg and hatchling survival was lower in wet years, and fledging rates were higher in warm years. Annual productivity of Orange River Peregrines correlated positively with the height of the river at the onset of breeding, and productivity of Soutpansberg Peregrines was higher in seasons following years of high rainfall. Elements of the physical structure of the nesting habitat (exposure of the nest ledge, height of the nest cliff) correlated positively with Peregrine breeding performance. Breeding success of Soutpansberg Lanners was largely unaffected by any of the environmental variables considered. Overall, it is proposed that Peregrine productivity reflected variation in the physical environment and its affect on prey availability.     

Characteristics of Peregrine and Lanner Falcon nesting habitats in South Africa

Jenkins, A.R. 2000. Choracteristics of Peregrine and Lanner Falcon nesting habitots in South Africa. Ostrich 71 (3&4): 416-424. Peregrine Falcon, Falco peregrinus, and Lanner Falcon, F. biarmicus, nesting habitats in South Africa are described in terms of nest ledge, nest cliff and scree slope parameters, ond the environmental context of each site. Data were collected in a tropical study area where Peregrines and Lannen occurred in sympatry, from an allopatric south temperate Peregrine population, and opportunistically for bath species from other sites throughout the country. Elevation, ledge size, cliff size ond vegetation structure accounted for about 80%of the variation in falcon nesting habitots between species and between populations within species. Peregrines used larger nest ledges on higher, more elevated cliffs than Lanners, overlooking mare open, structurally complex Vegetation. Temperate Peregrines used smaller ledges on lower cliffs, overlooking vegetation that provided less refuge for overflying prey than subtropical pairs. Temperote Peregrines selected nest sites to minimize the negative effects of spring roinfall. Tropical Peregrines may have selected sites to maximize hunting and provisioning efficiency.     

Conservation status and community structure of cliff-nesting raptors and ravens on the Cape Peninsula,South Africa

We detail the sizes, spatial distributions and trends in nest site selection of cliff-nesting raptor and raven populations resident in the mountains of the Cape Peninsula, South Africa. We also assess the conservation value of these populations to inform the future management of the newly-established Table Mountain National Park (TMNP), and examine the structure and interrelations within the raptor community. The combined number, dispersion and density of nests (n = 96 nests, mean inter-nest distance = 0.59km, density = 30.0 pairs/100km²) are comparable with those of high-density raptor populations studied elsewhere in Africa and the world. Densities of Verreauxs' Eagle Aquila verreauxii (n = 2, 12.01km, 0.6 pairs/100km², respectively) and Jackal Buzzard Buteo rufofuscus (n = 9, 4.63, 2.8 pairs/100km²), are low, Rock Kestrel Falco rupicolus (n = 44, 1.75km, 13.8 pairs/100km²) high and Peregrine Falcon Falco peregrinus (n = 19, 3.13km, 5.9 pairs/100km²) exceptional, relative to populations of the same or similar species in other areas. There are no comparable data for White-necked Raven Corvus albicollis (n = 22, 3.22km, 6.9 pairs/100km²). All species combined, and Peregrines in particular, significantly prefer high cliffs from the available habitat. Peregrines generally dominate the other species, may affect cliff site selection and dispersion in the rest of the community, and tend to locate their nests close to those of White-necked Ravens. Numbers of Verreauxs' Eagle are lower than recent historical levels, perhaps because key prey populations are depleted. Any future recovery of this large predator could subtly affect the entire assemblage. This cliff-nesting raptor community is a significant asset of the TMNP, and should be considered in management decisions taken in the Park, particularly those concerning the regulation of leisure activities in the vicinity of nesting areas.     

THE INFLUENCE OF HABITAT ON THE DISTRIBUTION AND ABUNDANCE OF PEREGRINE AND LANNER FALCONS IN SOUTH AFRICA

Jenkins, A.R. 1994. The influence of habitat on the distribution and abundance of Peregrine and Lanner Falcons in South Africa. Ostrich 65: 281–290.

The distribution and abundance of Peregrine and Lanner Falcons in South Africa was compared using recorded sightings from various sources, including the Southern African Bird Atlas Project. Falcon distributions were compared with the distribution of cliffs and vegetation, to quantify differences in the habitat preferences of the two species in the breeding and the non-breeding seasons. Lanner Falcons outnumbered Peregrine Falcons in most areas by at least 10:1. Peregrine Falcons were more habitat specific than Lanner Falcons, in terms of topographic and biotic requirements. Peregrine Falcons were largely restricted to high cliff areas throughout the year and there probably were no large-scale seasonal movements within the population. The bulk of the resident Peregrine Falcon population was found in the fynbos biome, in the southwestern Cape. Outside of this area, Peregrine Falcons were concentrated in woodlands. Lanner Falcons were less dependent on high cliffs, although cliff availability was important in defining the ranges of both species. Lanner Falcons were most common in the sour grasslands in the east of the country in the breeding season, with apparent movements in the non-breeding season into the fynbos, the Nama Karoo and the southern Kalahari. Overall, Peregrine Falcons favoured relatively closed habitats and Lanner Falcons favoured relatively open habitats. The differences in the two species' habitat preferences are proximate factors influencing distribution and abundance.     

Reduced genetic variation in Norwegian Peregrine Falcons Falco peregrinus indicated by minisatellite DNA fingerprinting

The Scandinavian Peregrine Falcon Falco peregrinus population went through a severe population bottleneck during the second half of the twentieth century, and was almost extinct during the 1970s. This event may have reduced the amount of genetic variation in the population. With this background, a comparative study, using multilocus, minisatellite DNA fingerprinting, was carried out on broods of the Peregrine Falcon, the Merlin Falco columbarius and the Eurasian Hobby Falco subbuteo from south-east Norway. Band-sharing analysis of DNA fingerprints was used to test whether broods of Peregrine Falcons showed a greater between-nest similarity in their fingerprint profiles than did broods of the two congeneric species breeding in the same region, which have not undergone any recent population bottlenecks. The results show that broods of Peregrine Falcons were significantly more similar to each other genetically than were broods of either Merlins or Eurasian Hobbies. Furthermore, there was a positive correlation between the similarity in minisatellite DNA and the similarity in a set of 11 microsatellite loci analysed for a subset of the Peregrine Falcon samples. The correlation supports the assumption that minisatellite fingerprints provide a reliable indicator of overall genetic similarity, i.e. relatedness, between breeding pairs in the population. Hence we can conclude that broods of Peregrine Falcons were genetically more related to each other than were broods of the other two species. The high similarity in minisatellite DNA between broods indicates a loss of genetic variation in the Peregrine Falcon population caused by the bottleneck, but this explanation can only be verified through a comparative genetic study of individuals sampled before and after the bottleneck event.     

ASPECTS OF THE POPULATION DYNAMICS OF CAPE VULTURES IN THE CAPE PROVINCE

Robertson, A. S. 1984. Aspects of the population dynamics of Cape Vultures in the Cape Province. Ostrich 55: 196–206.

Information gathered in 1981 and 1982 and collated from previous records on the numbers, spatial distribution, proportion of age classes, age and frequency of breeding, breeding success and causes of breeding failure, and the survival of immature and adult Cape Vultures Gyps coprotheres in the southern and southwestern areas of the Cape Province, South Africa, is presented. This sub-population of about 75 birds is apparently isolated from conspecifics in the rest of southern Africa; the implications of this are discussed. At the Potberg colony in both years an average of 85% of birds 5 years and older were involved in breeding attempts. The age of first breeding was 4–6 years. Nest sites were active for about two in every three years. Between 1975 and 1982, 0,51-0,67 nestlings were reared per active nest site (n=165). Four (possible maximum six) of 21 immatures were resighted one year after they had flown. Of 123 birds that had been ringed at Potberg to 1980, 14 (11%) were sighted in 1981; only four of 48(8%) colour-ringed birds 5 years old and older were breeding in 1981.     

DIET,HOME RANGE,HUNTING AND REPRODUCTIVE BEHAVIOUR OF A PAIR OF DICKINSON'S KESTREL FALCO DZCKZNSONZ IN THE KRUGER NATIONAL PARK,SOUTH AFRICA

Summary

BENN, G.A. &; KEMP, A.C. 1995. Diet, home range, hunting and reproductive behaviour of a pair of Dickinson's Kestrel Falco dickinsoni in the Kruger National Park, South Africa. Ostrich 66: 81–91.

During July-December 1992, the diet, home range, hunting and reproductive behaviour of a pair of Dickinson's Kestrel Falco dickinsoni was recorded in the Kruger National Park, South Africa. Numerically, for both sexes combined, invertebrates formed the majority (56%) of the diet, while separately the female caught 75% and the male 49% invertebrate prey. During courtship and incubation the male supplied the female with primarily vertebrate prey and both provisioned mainly vertebrates to the nestlings (male = 80%; female = 57%). The non-breeding home range of the female was 27.8 km², and the breeding home range of the male was 26.3 km2. Both utilised their home ranges differentially, the area within a 2 km radius of the nest (12.6 km²) being used proportionally more than the remaining area. The home range of the female was compared to that of other Falco spp. and was larger than would be expected based on body weight. Perch-hunting was the only technique utilised by both sexes, with 79–80% of observed strike attempts from dead trees. During the day, the 9.emale spent 87% and the male 77% of the time perch-hunting, with respective hunting success rates of 69% and 58%. During courtship, the female spent much of her time (94%) close to the nest, where the male supplied her with prey. During incubation, the male spent 95% of his time within 2 km of the nest tree, where he hunted to supply the female with prey at a rate of 0.3 items.hr^?1 and assisted in nest defence. On occasion the male entered the nest to relieve the female, and remained in the cavity on average for 134 min (n = 5). As the young got older, the female spent less time at the nest and provisioned more items to the nestlings. Overall, there was an increase in the rate of prey provisioning to the nestlings from 0.45 items.hr^?1 (10 days old) to 0.85 items.hr^?1 (21 days old). The male initially passed prey to the female but provisioned directly to older nestlings.     

Hunting mode and success of African Peregrines Falco peregrinus minor,does nesting habitat quality affect foraging efficiency?

Peregrine Falcon Falco peregrmus hunting behaviour was studied at nest-sites in three areas of South Africa over eight years. In Africa, resident Peregrines are mostly restricted to high cliffs, possibly because these structures provide optimal conditions for hunting. This hypothesis is examined in terms of the influence of nest-site quality, particularly cliff height, on foraging efficiency. Foraging mode varied considerably between sites, and males foraged more actively than females but there was little variation in the design of hunts between sexes, seasons or study areas. Individually, Peregrines spent 30–50% of the day on or near the nest cliff. On average, about 0.5 hunts were recorded per hour of observation. Foraging mode was not correlated with cliff height or elevation above the surrounding terrain, but Peregrine pairs occupying higher cliffs achieved greater hunting success rates. Most hunts were initiated from elevated perches on the nest cliff, and perch hunts were more successful than strikes made from the air. Success was highest in strikes at doves and small passerines, and over habitats with moderate cover. The height difference between Peregrine and prey at the start of a hunt positively and significantly affected hunting success. Overall, Peregrines were relatively sedentary and made extensive use of the nesting habitat as a foraging area. High nest cliffs contributed to foraging success by providing perch-hunting falcons with an effective height advantage over their prey.     

Environmental factors affecting patterns of distribution and co‐occurrence of two competing raptor species

Habitat selection is a complex process, that is affected by several factors, including habitat characteristics, environmental conditions, and both intra‐ and interspecific interactions. We analysed habitat preferences of two top avian predators, Peregrine Falcon Falco peregrinus, a medium‐sized diurnal raptor, and Eagle Owl Bubo bubo, a large nocturnal raptor. These two species are known to compete for preferred nest‐sites, and proximity to cliffs with Eagle Owls may reduce Peregrine breeding output through predation of young Falcons. We investigated the environmental factors affecting occurrence and coexistence of the two species and the potential role of habitat suitability in favouring co‐occurrence in 3519 km² of the central pre‐Alps of Italy, where the two species breed on cliffs and sometimes co‐occur on the same cliff. Peregrines settled on long, steep and favourably orientated cliffs in woodland landscapes close to urban areas. Eagle Owls settled on topographically similar cliffs, but in lower rainfall areas compared with cliffs occupied by Peregrines and cliffs unoccupied by either species. Sites where the two species co‐occurred were characterized by more horizontally extended cliffs compared with sites of exclusive occurrence of each species. An analysis of relative habitat suitability revealed that sites where the two species co‐occurred had the highest predicted probability of occupancy for both species, suggesting that those sites should be regarded as high‐quality sites. Breeding productivity of Eagle Owls was negatively affected by the co‐occurrence of Peregrines, whereas the effect of Eagle Owl proximity on Peregrine productivity varied according to cliff suitability for the Peregrines. Habitat selection had fitness consequences for Eagle Owls because breeding productivity increased with cliff length. Environmental conditions, particularly climatic factors, could allow the widespread coexistence of these competing raptors at the landscape scale, whereas at the local scale co‐occurrence could take place only on larger cliffs. These were preferred sites for both species, presumably because breeding at such sites offsets the costs of settling close to the competitor species.     

BREEDING BIOLOGY OF THE BATELEUR

Watson, R. T. 1990. Breeding biology of the Bateleur. Ostrich 61: 13–23.

Observations were made on the breeding biology of the Bateleur Terathpoius ecaudataus between 1981 and 1984, in the central region of the Kruger Nabonal Park. Nests were uniformly distributed with a mean inter-nest distance of 5,1 km and density of 3,1 nests/100km². Single-egg clutches were laid from January to June, and laying appeared to be suressed by unusually high rainfall events. The mean productivity was 0,47 young per pair per year, an a breeding failures were mainly due to failure to lay or predation. Breeding adults chaned nest sites within their territory on average once every 2,8 years, but territories and pairs were stable from year to year. Both members of a pair put equal time into care of the young.     

Vocal communication in Peregrine Falcons Falco peregrinus during breeding

The wailing call and the creaking call of the Peregrine Falcon Falco peregrinus were quantified throughout the breeding period. The creaking call was given mainly during the courtship period by both males and females, and its frequency at this time did not differ significantly between sexes. From the start of incubation and thereafter, the creaking call was uttered more frequently by males than by females; during the nestling period, it was mostly related to the male's transfer of food. The wailing call frequency never differed significantly between males and females and increased during the nestling period. This call was less linked with the presence of the mate than was the creaking call.     

Seasonal patterns in space use of Black Sparrowhawks Accipiter melanoleucus in an urban environment

Capsule: Urban Black Sparrowhawk males hunt mostly within 2.27?km of their nest during the breeding season (‘home range’ of 16.15?km²) and increased the distance slightly to 2.43?km outside of the breeding season (18.56?km²). We found high individual variation within and between six global positioning systems tagged breeding males, but no significant seasonal differences in the urban environment of Cape Town, South Africa.     

BREEDING BIOLOGY OF THE BEARDED VULTURE IN SOUTHERN AFRICA,PART III: THE POST-NESTLING DEPENDENCE PERIOD

Brown, C. J. 1990. Breeding biology of the Bearded Vulture in southern Africa, Part III: The post-nestling dependence period. Ostrich 6l: 43–49.

The post-nestling dependence period of the Bearded Vulture Gypaetus barbatus in southern Africa begins with the first flight of the young bird at 126 ± 2 days after latching (November-January) and ends during the pre-laying nod or the parent birds' next breeding attempt (April-June), a nod of about five months. For the first two weeks after first flit young bid remaine6 within about 200m of the nest, moving up to 800 m by the third week. By a month out of the nest young birds spent about 40% of the day in flight, moved up to 3 km from the nest, began bone-dropping and interacting with young birds from neighbouring nests. At six weeks they began to accompany their parents for part of some of their foraging trips, but returned to the nest alone, and by eight weeks they completed foraging forays with parents Pasting up to 3 h. At 2–3 months out of the nest young birds covered an area of about 42 km², excluding the foraging trips with parents, by 3–4 months, 78km² and 4–6 months, 168 km². Parent birds delivered food for at least five months after the young bird's first flight. Young birds left their natal areas of their own accord, usually during the first month of their parents' next breeding attempt.     

Radar observations of the stoop of the Peregrine Falcon Falco peregrinus and the Goshawk Accipiter gentilis

Measurements in 10-s intervals by a tracking radar showed average speeds of about 25 ms^-1 for a Peregrine Falcon Falco peregrinus and a Goshawk Accipiter gentilis during four stoops lasting 40–110 s, with angles of dive between 13^o and 64^o, and involving height losses between 450 and 1080 m. Maximum speeds during 10-s intervals were between 31 and 39 ms^-1 in the Peregrine Falcon, and close to 30 ms^-1 in the Goshawk. The observed speeds are well below the maximum possible terminal speeds in steep or vertical dives according to theoretical estimation. By adopting a moderate stooping speed, raptors may gain in hunting precision.     

ON THE BREEDING OF THE WHITE-RUMPED SWIFT (APUS CAFFER CAFFER) IN GATOOMA

Crawford, R. J. M., Cooper, J. &; Shelton, P. A. 1982. Distribution, population size, breeding and conservation of the Kelp Gull in southern Africa. Ostrich 53:164:177.

The Kelp Gull Lams dominicanus in Africa occurs coastally between Luanda, Angola and Delagoa Bay, Moçmbique. It breeds between Cape Cross Lagoon, South West Africa/Namibia and Riet River, eastern Cape, South Africa. Censuses of nests and breeding birds at all known southern African breeding localities in the period 1976–1981 indicated that 11 199 pairs bred at 52 localities; 79.5% of this population occurred in South Africa, 57,1% in the Saldanha Bay to Dassen Island region, southwestern Cape. Of the breeding pairs 83% occurred on offshore islands and rocks. Colony size at islands is related to their surface area andMayalso be influenced by food availability and the level of human disturbance. The species breeds in a wide variety of habitats ranging from cliffs and rock stacks to wooden platforms, lowlying vegetation among sand dunes and estuarine sandbars. Any available material is used in the construction of nests, whichMaybe as dense as 4/m² Clutch size is 2–3 eggs. In 1978 breeding took place earlier in South Africa than in South West Africa/Namibia. 92% of the population breeds m sites which are legally protected. Kelp Gulls have decreased or increased in numbers at some breeding localities but there is no clear overall trend. Any increases in colony size near urban areasMayresult in added airstrike hazards.     

Multi‐season occupancy models identify biotic and abiotic factors influencing a recovering Arctic Peregrine Falcon Falco peregrinus tundrius population

Critical information for evaluating the effectiveness of management strategies for species of concern include distinguishing seldom occupied (or low‐quality) habitat from habitat that is frequently occupied and thus contributes substantially to population trends. Using multi‐season models that account for imperfect detection and a long‐term (1981–2002) dataset on migratory Arctic Peregrine Falcons Falco peregrinus tundrius nesting along the Colville River, Alaska, we quantified the effects of previous year's productivity (i.e. site quality), amount of prey habitat, topography, climate, competition and year on occupancy dynamics across two spatial scales (nest‐sites, cliffs) during recovery of the population. Initial occupancy probability was positively correlated with area of surrounding prey habitat and height of nest‐sites above the Colville River. Colonization probability was positively correlated with nest height and negatively correlated with date of snowmelt. Local extinction probability was negatively correlated with productivity, area of prey habitat and nest height. Colonization and local extinction probabilities were also positively and negatively correlated, respectively, with year. Our results suggest that nest‐sites (or cliffs) along the Colville River do not need equal protection measures. Nest‐sites and cliffs with historically higher productivity were occupied most frequently and had lower probability of local extinction. These sites were on cliffs high above the river drainage, surrounded by adequate prey habitat and with southerly aspects associated with early snowmelt and warmer microclimates in spring. Protecting these sites is likely to encourage continued occupancy by Arctic Peregrine Falcons along the Colville River and other similar areas. Our findings also illustrate the importance of evaluating fitness parameters along with climate and habitat features when analysing occupancy dynamics, particularly with a long‐term dataset spanning a range of annual climate variation.     

Predator presence may benefit: kestrels protect curlew nests against nest predators

We studied whether the presence of breeding kestrels (Falco tinnunculus) affected nest predation and breeding habitat selection of curlews (Numenius arquata) on an open flat farmland area in western Finland. We searched for nests of curlews from an area of 6 km² during 1985–1993. For each nest found, we recorded the fate of the nest, and the distance to the nearest kestrel nest and to the nearest perch. We measured the impact of breeding kestrels on nest predation by constructing artificial curlew nests in the vicinity of ten kestrel nests in 1993. Curlew nests were closer to kestrel nests than expected from random distribution, eventhough kestrels fed on average 5.5% of curlew chick production. Predation risk by kestrels was lower than predation risk by corvids and other generalist predators, which predated 9% of curlew nests surviving farming practices and an unknown proportion of chicks. Artificial nest experiment showed that nest predation was lower close to kestrel nests than further away suggesting that the breeding association of curlews and kestrels was a behavioural adaptation against nest predation. Thus, the presence of a predator may sometimes be beneficial to prey, and prey animals have behavioural adaptations to these situations.     

A survey of the apes in the Dzanga-Ndoki National Park, Central African Republic: a comparison between the census and survey methods of estimating the gorilla (Gorilla gorilla gorilla) and chimpanzee (Pan troglodytes) nest group density

A survey of apes was carried out between October 1996 and May 1997 in the Dzanga sector of the Dzanga‐Ndoki National Park, Central African Republic (CAR), to estimate gorilla (Gorilla gorilla gorilla) and chimpanzee (Pan troglodytes) densities. The density estimates were based on nest counts. The strip transect census and the line transect survey method (Standing Crop Nest Count) were used to estimate the gorilla nest group density. The strip transect has been most commonly used to date. It assumes that all nest groups within the width of the strip are detected, but as this assumption is easily violated in the dense tropical rain forest, the line transect survey was also used. In this method, only the nest groups on the transect line itself should be detected. This method proved to be an adequate and easy technique for estimating animal densities in dense vegetation. The gorilla density of 1.6 individuals km^?2 (line transect survey method) found for the Dzanga sector is one of the highest densities ever reported in the literature for the Western lowland gorilla. The density estimate for chimpanzees was 0.16 individuals km^?2 (census method). The results of this study confirm the importance of the Dzanga‐Ndoki National Park for primate conservation.