Spotted hyaena Crocuta crocuta feeding ecology and selectivity of large herbivorous prey in the Namib desert

We have investigated the relationship between spotted hyaenas in the south Namib Desert and large herbivorous prey and have summarized an updated overview of predator‐prey relationships in this resource‐limited arid environment. Over the 52‐month study, we recorded the densities (#/km⁻², ±SE) of the four local large herbivorous prey species: gemsbok (1.229, ±0.50), springbok (1.352, ±0.48), ostrich (0.648, ±0.23), and greater kudu (0.343, ±0.00). A fecal analysis was performed on 146 collected spotted hyaena scats, and prey items were identified and hairs cross‐follicle analyzed to the species level. Spotted hyaena diet at the study area remained opportunistic with 240 identified prey items representing eight differing prey species being recorded, ranging from ostrich eggs to large ungulates. The Ivlev''s Electivity Index was used to determine which large herbivorous prey was most selected for. Although gemsbok had a higher representation of prey items in the sampled scats, all sampled large herbivorous prey species scored below 0 and are thus generally avoided in relation to their availability in the environment. If any prey preferences are expressed by spotted hyaena in the Namib, it can be presumed to be a nonsampled prey species. We therefore promote further detailed investigations into all other prey species present, and seasonal variations of prey densities and scat sampling, within the study environment.     

Dietary partitioning of three large carnivores in Majete Wildlife Reserve,Malawi

Between 2011 and 2012, the carnivore guild in Majete Wildlife Reserve (MWR), Malawi, was restored following the reintroduction of lion (Panthera leo) and leopard (Panthera pardus). The aim of this study was to describe and compare the diet of lion, leopard and resident spotted hyaena (Crocuta crocuta) using scat analysis. Lions and spotted hyaenas displayed the greatest dietary overlap (O_ab = 0.88) and selected mainly medium- to large-bodied prey species. Lions had a mean preferred prey weight of 120.33 ± 42.14 kg (SE), with warthog (Phacochoerus africanus) and waterbuck (Kobus ellipsiprymnus) making up 60.64% of relative biomass consumed. Spotted hyaenas had a mean preferred prey weight of 102.40 ± 41.69 kg and had a more generalised diet (B_a = 0.46) compared to lions (B_a = 0.36). In contrast, leopards occupied a dietary niche substantially lower than that of lions and spotted hyaenas, selecting relatively smaller prey with a mean preferred prey weight of 27.50 ± 6.74 kg. Our results suggest that coexistence between the resident hyaena and reintroduced lion and leopard in MWR is facilitated by dietary partitioning. We advise long-term monitoring of reintroduced carnivores in small, enclosed reserves to assess their impacts on predator and prey populations.     

Prey choice by marten during a decline in prey abundance

Summary We examined variation in diet choice by marten (Martes americana) among seasons and between sexes and ages from 1980–1985. During this period prey populations crashed simultaneously, except for ruffed grouse (Bonasa umbellus) which was common at the beginning and end of the study, and masked shrews (Sorex cinereus) which were abundant in 1983. Marten were catholic in selection of prey and made use of most available mammalian prey, ruffed grouse, passerine birds, berries, and insects. Diet niche was widest during the latter three years when prey was scare, particularly in late winter. Diet niche breadth was negatively correlated with abundance of all common prey species. Proportion of small prey species in the diet was correlated with absolute abundance of those species, but proportion of some large prey was related to their relative abundance. Diet choice varied among years and among seasons. Berries and insects were common in summer diets while large prey, particularly varying hare (Lepus americanus), were more frequent in winter diet than in summer diet. We found little evidence that any small mammal species was a preferred prey. Sexual size dimorphism between the sexes did not affect prey choice, nor did age. Reduced foraging effort in winter resulted in a wider diet niche only when prey was scarce. The only prediction of optimal foraging models fully supported by our data was a wider diet niche with reduced prey abundance. However, among the three most profitable prey species choice was dependent on the absolute abundance of the most profitable type (varying hare). We suggest that marten primarily forage for large prey but employ a strategy which results in encounters with small prey as well. These small prey are eaten as they provide energy at minimal cost, between captures of large prey.     

Dietary partitioning by five sympatric species of stingray (Dasyatidae) on coral reefs

Dietary characteristics and the degree of dietary partitioning by five species of sympatric stingray were assessed using stomach content and sediment analyses within a coral reef lagoon at Ningaloo Reef, Western Australia (the cowtail Pastinachus atrus, blue‐spotted fantail Taeniura lymma, blue‐spotted mask Neotrygon kuhlii, porcupine Urogymnus asperrimus rays and the reticulate whipray Himantura uarnak). A total of 2804 items were recovered from the stomachs of 170 rays and 3215 individual taxa from the environment, which were used in selectivity analyses. Twenty‐four prey taxa were identified from stomach contents and pooled into 10 taxonomic categories for analysis, of which annelids, prawns, brachyurans and bivalves were the most abundant, together accounting for 96% of the diet. Himantura uarnak had the greatest interspecific dissimilarity in diet, consuming a larger proportion of crustaceans, notably penaeids (41% of total diet) than the other four species of rays, all of which had diets dominated by annelids (71–82% of total diet). Crustacean specialization by H. uarnak may exist to maximize resources and reduce competition among sympatric species. The remaining species may partition resources on the basis of space, rather than diet.     

Prey preferences of the spotted hyaena (Crocuta crocuta) and degree of dietary overlap with the lion (Panthera leo)

Spotted hyaenas Crocuta crocuta were once considered mere scavengers; however, detailed research revealed that they are very efficient predators. Information on what spotted hyaenas actually prefer to prey on and what they avoid is lacking, as well as the factors that influence prey selection. Data from 14 published and one unpublished study from six countries throughout the distribution of the spotted hyaena were used to determine which prey species were preferred and which were avoided using Jacobs' index. The mean of these values for each species was used as the dependent variable in multiple regression, with prey abundance and prey body mass as predictive variables. In stark contrast to the rest of Africa's large predator guild, spotted hyaenas do not preferentially prey on any species. Also surprisingly, only buffalo, giraffe and plains zebra are significantly avoided. Spotted hyaena most prefer prey within a body mass range of 56–182 kg, with a mode of 102 kg. The dietary niche breadth of the spotted hyaena is similar to that of the lion Panthera leo , and the two species have a 58.6% actual prey species overlap and a 68.8% preferred prey species overlap. These results highlight the flexible and unselective nature of spotted hyaena predation and are probably a reason for the species' success throughout its range, despite a large degree of dietary overlap with lions.     

Densities of spotted hyaena (Crocuta crocuta) and African golden wolf (Canis anthus) increase with increasing anthropogenic influence

We report densities of spotted hyaena (Crocuta crocuta) and African golden wolf (Canis anthus) in Enderta district in northern Ethiopia with high human and low natural prey densities. We estimated spotted hyaena and African golden wolf abundance and characterized their spatial distribution with three methods we surveyed four road-transects for 66 nights during dry (n = 41) and wet (n = 25) seasons, we used 34 calling stations and we mapped all active spotted hyaena dens at the time of the survey. The density of spotted hyaena and African golden wolf increased with proximity to towns where human density was higher. A total of 562 spotted hyaena and 63 African golden wolf responded to calling stations, leading to estimates of 1145 spotted hyaena and 166 African golden wolf in Enderta district. This method also found a significantly higher spotted hyaena and African golden wolf abundance in high human density areas. Maximum response radius was 2.8 km for spotted hyaena and 2.5 km for African golden wolf, and response probability was 0.83 for spotted hyaena and 0.8 for African golden wolf, respectively. We found 40 active spotted hyaena dens with 1507 remnants of prey, and the majority of the dens were located close to rivers and villages. Our findings show a positive relationship between spotted hyaena, African golden wolf and human concentrations that might demonstrate a case of exceptional coexistence of humans and carnivores, both at high densities. We suggest further investigations into co-adaptations between humans and predators in the study area.     

Mammalian Diet and Broad Hunting Strategy of the Dingo (Canis familiaris dingo) in the Wet Tropical Rain Forests of Northeastern Australia1

The diet of dingoes (Canis familiaris dingo) in the Australian Wet Tropics was examined by analyzing 383 dingo scats collected throughout the region for the presence of mammal prey remains. The scats yielded 29 native and 4 introduced mammal prey species from 14 families. The most important species in terms of percentage occurrence in the scats were Melomys cervinipes (22.2%), hoodon macrourus (17.0%), Perameles nasuta (12.5%), and Thylogale stigmatica (12.5%). The most important families were Muridae (37.1%), Peramelidae (29.5%), and Macropodidae (25.8%). Examination of small‐scale habitat preferences revealed species that preferentially use the forest edge ranked significantly higher in the diet than those that do not, and species that are terrestrial ranked higher in the diet than those that are arboreal. Relative abundance was also a significant factor in the ranked dietary occurrence of each species, with abundant species ranked significantly higher than those that are less abundant. These results suggest that dingoes in the Australian Wet Tropics are opportunistic predators of a wide variety of mammal species, with abundant terrestrial and forest edge‐dwelling taxa the most susceptible to predation.     

Seasonal variation in prey preference,diet partitioning and niche breadth in a rich large carnivore guild

Large carnivore community structure is affected by direct and indirect interactions between intra-guild members. Co-existence between different species within a carnivore guild may occur through diet, habitat or temporal partitioning. Since carnivore species are highly dependent on availability and accessibility of prey, diet partitioning is potentially one of the most important mechanisms in allowing carnivores to co-exist. Intra-guild interactions may vary over time as carnivore prey preference and diet overlap can change due to seasonal changes in resource availability. We conducted scat analysis to compare the seasonal changes in prey preference, diet partitioning and niche breadth of four large carnivore species, namely leopard Panthera pardus, spotted hyena Crocuta crocuta, brown hyena Parahyaena brunnea and wild dog Lycaon pictus in central Tuli, Botswana. Large carnivores in central Tuli display a high dietary overlap, with spotted hyena and brown hyena displaying almost complete dietary overlap and the other carnivore species displaying slightly lower but still significant dietary overlap. Dietary niche breadth for both hyena species was high possibly due to their flexible foraging strategies, including scavenging, while leopard and wild dog showed a relatively low niche breadth, suggesting a more specialised diet. High dietary overlap in central Tuli is possibly explained by the high abundance of prey species in the area thereby reducing competition pressure between carnivore species. Our research highlights the need to assess the influence of diet partitioning in structuring large carnivore communities across multiple study sites, by demonstrating that in prey rich environments, the need for diet partitioning by carnivores to avoid competition may be limited.     

Diet composition of the Thornback Ray,Raja clavata Linnaeus, 1758 (Elasmobranchii: Rajidae) in the Turkish Aegean Sea

The diet of Raja clavata (Thornback Ray) was studied in 2008–2009 in S??ac?k Bay in the eastern Mediterranean, based on 187 stomach contents obtained by commercial trawl operations. 40 different prey species were found. Mysidacea, Parapenaeus longirostris and Plesionika sp. were the most abundant prey items. The results indicate that the main prey varies considerably depending on the ecological characteristics of the habitat.     

Feeding ecology and prey preferences of a piscivorous fish in the Lagoa do Peixe National Park, a Biosphere Reserve in Southern Brazil

We investigated the diet, feeding strategy, size-related dietary shifts and prey preferences of South American Hoplias aff. malabaricus in an internationally recognized but poorly investigated Biosphere Reserve in southern Brazil. Fish were caught between April 2008 and March 2009 using a variety of fishing gear. The analysis of 113 individuals revealed a diet essentially composed of fish (16 species), particularly characid species (9). The diet became more diverse and contained larger fish prey with increasing predator size. Feeding strategy analysis revealed a clear specialization towards the consumption of fish. However, individuals did not prey upon particular prey species, instead opportunistically consuming many different fish species, which could be a strategy to avoid intraspecific competition. Characid species were the most important prey, followed by poecillids. A multi-gear sampling of the ichthyofauna revealed that these prey species were the most abundant (Characidae: 61.3%, Poeciliidae 18.8%) of the 14 fish families occurring at the study site, suggesting that the predator exploits the most abundant fish resources available rather than the rarer fish prey. These findings suggest that potential top-down controls exerted by H. aff. malabaricus in this system follow specific food web pathways that seem to be mediated by the abundance of prey resources.     

4. BIRD PROTECTION POLICIES AND LAWS

Walter, C. B., Cooper, J. &; Suter, W. 1987. Diet of Swift Tern chicks in the Saldanha Bay region, South Africa. Ostrich 58:49-53.

The diet of the Swift Tern Sterna bergii was investigated over a ten-year period off the west coast of South Africa by collecting regurgitations from chicks during ringing operations. A total of 1311 prey items of 25 identifiable species (20 of which were fish) was collected. Fish formed 86% of all the prey items. Other prey species included cephalopods, crustaceans and insects. 60% by number of prey taken consisted of pelagic shoaling fish, of which Cape Anchovy Engraulis japonicus occurred most frequently and was the most abundant prey species in seven of the nine years in which samples were collected. Weekly collections in 1984 confirmed that pelagic shoaling fish, in particular Cape Anchovy, were the most abundant prey taken during the chick-rearing period. Prey size varied from 7 to 138 mm in length and from 0,l to 30,0 g in mass.     

Anthropogenic influences on spotted hyaena diet in the Kruger National Park,South Africa

Rapid urban expansion has led to an increase in carnivores that live close to human dominated environments. Some carnivore species have successfully adapted to these novel conditions and taken advantage of opportunities associated with human habitation. Whilst many studies have compared carnivores living in protected areas to those in an urban setting, few have looked at the relationships between carnivores and human habitation within protected areas. In this study, we examined the effects of human habitation on the diet of spotted hyaenas (Crocuta crocuta) in the Kruger National Park (KNP), South Africa. Our results suggested a limited effect of anthropogenic resources on spotted hyaena diet in the KNP. We found neither temporal nor spatial variation in the amount of, nor types of, anthropogenic material in spotted hyaena scats, despite observations of more road side litter close to large anthropogenic sites. We therefore suggest that anthropogenic resources may not have been utilised completely according to abundance. We encourage further research evaluating potential secondary effects of human activity and infrastructure on spotted hyaena diet and also stable isotope approaches that may provide further insights into the importance of anthropogenic food for spotted hyaenas inside the KNP.     

Trophic and Spatial Niches of two Large-sized Species of Leptodactylus (Anura) in Southeastern Brazil

Leptodactylus ocellatus (LO) and L. labyrinthicus (LL) are known to prey on other frogs. Here we compare their food habits based on the analysis of stomach contents and their spatial distribution when in sympatry. LO was found most frequently near stream banks, and LL on the margins of lakes and ponds. LO was found within 10 m of permanent water bodies; LL frequently used ponds far from lakes and rivers. Coleoptera, Formicidae, and Isoptera comprised 52% of the prey types identified in the LO sample, whereas Coleoptera and insect larvae represented 58% of the prey items of LL. Frogs were not frequent in the diet of either species but, in volume, represented the second most important category for LO and the first for LL. LO showed a larger trophic niche breadth than LL. The trophic niche overlap between the two species was 68.3% for percentage of prey items. The present work confirms the relative importance of frogs in the diet of both species. The greater capacity of LL in moving far away from permanent water bodies may generate better opportunities for prey selection and a narrower trophic niche breadth. The large range of prey used by these two species indicates they are generalist/opportunistic feeders.     

Diet,trophic interactions and possible ecological role of commercial sharks and batoids in northern Peruvian waters

The Peruvian sea represents one of the most productive ocean ecosystems and possesses one of the largest elasmobranch fisheries in the Pacific Ocean. Ecosystem-based management of these fisheries will require information on the trophic ecology of elasmobranchs. This study aimed to understand the diet, trophic interactions and the role of nine commercial elasmobranch species in northern Peru through the analysis of stomach contents. A total of 865 non-empty stomachs were analysed. Off northern Peru, elasmobranchs function as upper-trophic-level species consuming 78 prey items, predominantly teleosts and cephalopods. Two distinctive trophic assemblages were identified: (a) sharks (smooth hammerhead shark Sphyrna zygaena, thresher shark Alopias spp. and blue shark Prionace glauca) that feed mainly on cephalopods in the pelagic ecosystem; and (b) sharks and batoids (Chilean eagle ray Myliobatis chilensis, humpback smooth-hound Mustelus whitneyi, spotted houndshark Triakis maculata, Pacific guitarfish Pseudobatos planiceps, copper shark Carcharhinus brachyurus and school shark Galeorhinus galeus) that feed mainly on teleosts and invertebrates in the benthonic and pelagic coastal ecosystem. This study reveals for the first time the diet of T. maculata and the importance of elasmobranchs as predators of abundant and commercial species (i.e., jumbo squid Dosidicus gigas and Peruvian anchovy Engraulis ringens). The results of this study can assist in the design of an ecosystem-based management for the northern Peruvian sea and the conservation of these highly exploited, threatened or poorly understood group of predators in one of the most productive marine ecosystems.     

Trophic ecology of two Pithecopus species (Anura: Phyllomedusidae) living in syntopy in southern Bahia,Brazil

To coexist, two species should use available resources in different ways. These differences may happen in three different dimensions: temporal, spatial and trophic. In frogs, differences in trophic dimensions are mainly due to different sizes and types of ingested prey. We studied the diet of two syntopic Pithecopus species, addressing prey selectivity and sharing of food resources. Fieldwork was undertaken at the Michelin Ecological Reserve, southern Bahia, between the years 2011 and 2012. Stomach contents were retrieved using a flushing procedure and data on prey availability was obtained. Of the 16 invertebrate categories found in the environment, 11 were consumed by P. rohdei and 12 by P. nordestinus, features that characterize a generalist diet. The most abundant category in the diet of P. nordestinus was Diptera while Hemiptera was the most consumed prey category for P. rohdei. Trophic niche overlap was high considering the size of ingested prey and lower for categories. The selectivity index showed that both species used the resources available in the environment in a slightly different way. The differences found concerning trophic ecology of these two species seem to be sufficient to allow coexistence in the studied area.     

DNA metabarcoding for dietary analysis of Holland's carp (Spinibarbus hollandi) to evaluate the threat to native fishes in Taiwan

DNA metabarcoding analysis for gut contents has been shown to compensate the disadvantage of traditionally morphological identification and offer higher resolution of prey items in an efficient way. Holland's carp (Spinibarbus hollandi) is a freshwater fish native to southern and eastern Taiwan. In the past two decades, this species has been introduced as a sport fish into the river basins of northern and western Taiwan. The large body size and active predation make it a potential threat for native fishes, but which native species are preyed by Holland's carp remains unknown. In this study, the diet from the gut contents of Holland's carp from the Zhonggang River, an invaded basin, was examined using DNA metabarcoding from 51 individuals and by morphological examinations on 140 samples. Detritus of plants were found in 83.6% samples (117 individuals). Twenty fish species of seven families were identified by DNA metabarcoding, including species of all water layers. Taiwan torrent carp (Acrossocheilus paradoxus) and Rhinogobius spp. are the most common prey items. Based on the results of this study, Holland's carp is considered an opportunistic omnivore because of its diverse diet items, which is an important trait for successful invasive fish species. The population decline of Opsariichthys pachycephalus may not result from the invasion of Holland's carps. Nonetheless, the time lag between successful invasion and the samplings of this study may be a concern because the population size of O. pachycephalus may have declined and become difficult to prey. The Holland's carps consumed the least species in winter; nonetheless, the occurrence frequencies of preys among seasons were not significantly different probably because of limited temperature fluctuation. The smallest Holland's carps consumed the least prey species compared to other size categories, similar to the relationship of prey species number to size of invasive largemouth bass (Micropterus salmoides).     

The ecology of large carnivores in the highlands of northern Ethiopia

The degradation and fragmentation of the northern Ethiopian highlands has resulted in frequent encounters of large carnivores with humans and their livestock. We interviewed 500 randomly selected households to estimate economic impact of livestock predation by spotted hyaena (Crocuta crocuta), leopard (Panthera pardus) and jackal (Canis aureus aureus) in the highlands of northern Ethiopia. The annual mean economic loss per household was approximately U.S.$ 20.2, about 7% of the average annual income of households in the area. Households surveyed reported losses of a total of 3122 livestock to hyaena, leopard and jackal predation over the past 5 years. This loss equated to a total financial loss of U.S.$ 50,381 . Livestock predation incidents of spotted hyaena, leopard and jackal demonstrated that spotted hyaena had a preference for dog, donkey, goat and sheep; leopard for goat, dog and sheep; and jackal for goat and sheep. Livestock predation of spotted hyaena and leopard were mainly during the night. We conclude that assessing depredation problems is important to develop actions for management of either livestock practices or wildlife conservation.     

The effects of prey size on diet differentiation of seven passerine species at two spring stopover sites

Prey size was evaluated for seven passerine trans-Saharan migrant species at two spring stopover sites in Sardinia, Italy. The species considered were Pied Flycatcher Ficedula hypoleuca, Spotted Flycatcher Muscicapa striata, Redstart Phoenicurus phoenicurus, Garden Warbler Sylvia borin, Whitethroat Sylvia communis, Willow Warbler Phylloscopus trochilus and Wood Warbler Phylloscopus sibilatrix. The analysis was made for three prominent prey types: beetles (Coleoptera), ants (Hymenoptera: Formicidae) and “flying prey” (wasps and bees [Hymenoptera, excluding ants] and flies, Diptera, pooled), The prey size distribution in the diets of some species was very similar to that caught in our insect traps, showing that our estimates of availability are, at least partially, relevant. On the whole, diets deviated from food available in a species consistent way. The size distributions of “flying prey” differed between the two sites but were almost constant in the birds' diets. In contrast, size distributions of available beetles and ants at the sites were similar but were different in the birds' diets. Different feeding behaviour of the birds, in terms of physiological constraints during migratory stopovers, is discussed. Paired species comparisons show that the diets of most species differ significantly in the distribution of the size classes of at least some prey types. The conclusions drawn from the comparisons of the size distributions of all prey items collected from a bird species in one season are very similar to the conclusions drawn from comparisons based on the presence/absence of a size class per faecal sample. We compared the similarities of diet with and without using information on prey size. With the exception of the Pied Flycatcher and the Redstart at one of the study sites, size information did not add to diet segregation. Certain size classes within prey types tended to be common in the diet of these migrant passerines. However, specialization on certain size classes within broad taxonomic categories was not evident.     

Diet and prey selection of sympatric tropical skinks

Most skinks are opportunistic predators, taking available prey from the environment as it is encountered. Variation in their diet composition is thought to reflect differences in prey abundance in the environment. We studied diet composition and prey selection in a community of three sympatric skink species (genus Carlia) in northern Australia by comparing contents of skink stomachs with arthropod prey available in their habitat. Carlia were entirely carnivorous and fed on a range of arthropod prey. We found high overlap in diet and prey size among the three species and between the wet and dry seasons, but found that skinks generally focused their foraging efforts on prey types and prey sizes that were not abundant in the habitat. Spiders (Aranea), orthopterans, blattarians, isopods and termites (Isoptera) were important prey of skinks, but these arthropods were rarely trapped in the environment. Skinks also frequently consumed large‐bodied prey, despite the higher relative abundance of small prey in the environment. Skinks were more selective in their foraging and diet than previously assumed. Selection of prey by consumers is a fundamental ecological process, important to consumers for maintaining energy requirements to grow and reproduce, but equally important to the community dynamics of the prey consumed.