Quantitative characteristics of nutrition in free-ranging reindeer (<Emphasis Type="Italic">Rangifer tarandus</Emphasis>) and musk oxen (<Emphasis Type="Italic">Ovibos moschatus</Emphasis>) on Wrangel Island

In 2004 to 2006, studies on free-ranging reindeer and musk oxen on Wrangel island were performed to estimate the nutrient value, daily intake, and digestibility of forage in different seasons of the year. Forage digestibility was determined from the ratio between the contents of indigestible components (lignin) in forage and animal feces. Daily forage intake was calculated from data on daily feces excretion and forage digestibility. The amount of feces and parameters of life activity of individual animals were estimated by following their 24-hour tracks. The results show that the daily intake of forage (dry weight) in musk oxen amounts to 7.8 kg in the summer period and decreases to 6.1 kg in the snow period (March–April). Grazing reindeer in the snow period consume 3.9 kg of forage per day. Forage digestibility in reindeer reaches 56% in March to April and decreases to 52% in June. In musk oxen, forage digestibility in different seasons (March, June, September) varies within a similar range (53–57%). Nutrition parameters (diet composition, forage intake rate and digestibility) of reindeer and musk oxen on grazing grounds of Wrangel Island are similar. Metabolizable energy consumption in both animals during the winter period is at the maintenance level (917–930 kJ/kg0.75 body weight). In the summer period, this parameter in musk oxen increases to 1163 kJ/kg0.75 body weight to meet the energy demand of the animals.     

Diet and activity budget of <Emphasis Type="Italic">Rhinopithecus roxellana</Emphasis> in the Qinling Mountains,China

We collected data on diet and daytime activity budget, and investigated the phenology of food trees and food abundance for a group of Rhinopithecus roxellana on the East Ridge of Yuhuangmiao in the Qinling Mountains from November 2001 to December 2003. We calculated the seasonal activity budget using data collected by scan sampling from 84 full-day observations (winter 16, spring 18, summer 28, autumn 22 days). During scan sampling we recorded behavioral states, and the food items and species consumed. The subjects consumed 84 plant species, including trees and shrubs of 29 families, and lichens. Food species varied seasonally. The overall diet of R. roxellana consisted of 29.4% fruit/seeds, 29.0% lichens, 24.0% leaves, 11.1% bark, 4.2% buds, 1.3% twigs and 1.0% unidentified items. Because the abundance of different food items varied seasonally, the monkeys had to shift their major food items seasonally. The annual activity budget of R. roxellana was 36.2% time spent resting, 35.8% feeding, 22.9% moving, and 5.1% other behavior. Seasonal changes in activity budget were observed. R. roxellana spent more time moving in autumn, when the quality of the food might be highest, and least time moving in winter when the food quality might be lowest. Thus, this type of monkey has a passive foraging strategy.     

Dietary Profile of <Emphasis Type="Italic">Rhinopithecus bieti</Emphasis> and Its Socioecological Implications

To enhance our understanding of dietary adaptations and socioecological correlates in colobines, we conducted a 20-mo study of a wild group of Rhinopithecus bieti (Yunnan snub-nosed monkeys) in the montane Samage Forest. This forest supports a patchwork of evergreen broadleaved, evergreen coniferous, and mixed deciduous broadleaved/coniferous forest assemblages with a total of 80 tree species in 23 families. The most common plant families by basal area are the predominantly evergreen Pinaceae and Fagaceae, comprising 69% of the total tree biomass. Previous work has shown that lichens formed a consistent component in the monkeys’ diet year-round (67%), seasonally complemented with fruits and young leaves. Our study showed that although the majority of the diet was provided by 6 plant genera (Acanthopanax, Sorbus, Acer, Fargesia, Pterocarya, and Cornus), the monkeys fed on 94 plant species and on 150 specific food items. The subjects expressed high selectivity for uncommon angiosperm tree species. The average number of plant species used per month was 16. Dietary diversity varied seasonally, being lowest during the winter and rising dramatically in the spring. The monkeys consumed bamboo shoots in the summer and bamboo leaves throughout the year. The monkeys also foraged on terrestrial herbs and mushrooms, dug up tubers, and consumed the flesh of a mammal (flying squirrel). We also provide a preliminary evaluation of feeding competition in Rhinopithecus bieti and find that the high selectivity for uncommon seasonal plant food items distributed in clumped patches might create the potential for food competition. The finding is corroborated by observations that the subjects occasionally depleted leafy food patches and stayed at a greater distance from neighboring conspecifics while feeding than while resting. Key findings of this work are that Yunnan snub-nosed monkeys have a much more species-rich plant diet than was previously believed and are probably subject to moderate feeding competition.     

Fodder resources and feeding of semifree bison (<Emphasis Type="Italic">Bison bison</Emphasis>) on a steppe pasture in the Western Manych valley

In 2012–2013, the species composition, aboveground phytomass, and nutrition of freely ranging bison were investigated on a natural steppe pasture of the Western Manych valley. The aboveground mass of plants on the investigated pasture varied from 16.1 to 19.4 c/ha. The composition of the plants consumed by bison and their share in the bison’s diet were determined by microscopy of feces. In the snowless season, graminoids was the basis of the bison’s diet (79–87%). The use of forbs varied from 4.7 to 17.5%. Sedges were present in the forage in summer; they amounted to 6.5–15.4%. The quantitative assessment of the food selectivity was determined using the ratio of the share of a plant species in the diet to its portion in the plant community of the pasture. The most selected were Festuca valesiaca (the selectivity is 12.0), Agropyron sp. sp. (1.7), Polygonum patulum (1.2), and Carex sp. sp. (1.1). In other forage plants (Poa bulbojsa, Tanacetum achileifolium, and other forbs), the selectivity was 0.01–0.3. The nutritional value of fodder vegetation and food indexes (daily intake, digestibility of forage, consumption of metabolizable energy) were estimated. The digestibility was determined by the ratio of inert (undigestible) components (silicon, lignin) in the diet to their amount in the feces. The daily intake of forage was calculated based on the mass of released feces and digestibility of forage. In the snowless season, bison consumed from 6.3–7.0 to 9.2–9.9 kg/ind. (dry weight) per day. The maximum consumption (9.9 kg/ind.) was observed in summer. The digestibility of forage changed from 45 to 53% (the average is 50%). The consumption of metabolizable energy in different seasons varied from 0.60 to 0.91 MJ/kg^0.75/day, which corresponded to maintenance energy.     

Feeding Ecology of <Emphasis Type="Italic">Trachypithecus pileatus</Emphasis> in India

We observed a group of capped langurs for 12 mo in the Pakhui Wildlife Sanctuary, Arunachal Pradesh, India. We recorded the time of feeding on different food plant species, food categories, and the feeding heights of monkeys in trees. Capped langurs spent 68% of their feeding time on leaves, 16% on flowers, and 16% on fruits. Feeding on leaves was consistently high (p < 0.01) during the year, with the highest feeding in May (85%) and the lowest in January (47%). The seasonal difference in feeding on leaves is significant (p < 0.05): it was higher in summer and during monsoon. The feeding time on flowers was maximal (35%) in March and that on fruits and seeds was minimal (38%) in January. Langurs ate 52 plant species throughout the year. The largest number of plants (6) were species of Moraceae, and langurs spent more feeding time (20%) on them alone. The number of plants eaten per month varied significantly (p < 0.05). Langurs ate Gmelina arborea, Albizzia lucida, Ficus glomereta, and Makania micrantha throughout the year. They spent 44% of their feeding time in terminal canopies and their average feeding height was 30–35 m. This is the first study to examine the feeding ecology of capped langurs and provides baseline data for the species.     

Diet selection of the southern vizcacha (<Emphasis Type="Italic">Lagidium viscacia</Emphasis>): a rock specialist in north western Patagonian steppe,Argentina

The southern vizcacha (Lagidium viscacia) is a rock specialist that inhabits small colonies in isolated rocky outcrops of northwestern Patagonia. This study analyzes its diet selection in relation to food availability, establishes the degree of dietary specialization, and discusses the potential competition with exotic herbivores. Diet composition and food availability were determined in summer and winter in eight rocky outcrops by microhistological analysis of fecal pellets, and food availability was estimated by the Braun Blanquet cover abundance scale. Vegetation cover differences were detected by using a random analysis of variance (ANOVA) factorial block design, and dietary preferences were determined by the confidence interval of Bonferroni. The southern vizcacha showed a specialized feeding behavior despite the consumption of a wide variety of items. Their diet was concentrated on a few types of food, mainly grasses, and the trophic niche was narrow and without seasonal variations. In winter, when food was scarce and of lower quality than summer, diet was dominated by Stipa speciosa, suggesting a selection according to the selective quality hypothesis. Our results (narrow trophic niche, restricted activity near rocky outcrops, and a diet with high proportions of low-quality grasses) showed that the vizcacha is an obligatory dietary specialist, and these characteristics made it highly vulnerable to changes in food availability. In this scenario, overgrazing caused by alien species with similar diets, as the European hare and livestock, could negatively affect their colonies.     

Winter ecology of Arctic charr (<Emphasis Type="Italic">Salvelinus alpinus</Emphasis>) and brown trout (<Emphasis Type="Italic">Salmo trutta</Emphasis>) in a subarctic lake,Norway

We studied habitat choice, diet, food consumption and somatic growth of Arctic charr (Salvelinus alpinus) and brown trout (Salmo trutta) during the ice-covered winter period of a subarctic lake in northern Norway. Both Arctic charr and brown trout predominantly used the littoral zone during winter time. Despite very cold winter conditions (water temperature <1°C) and poor light conditions, both fish species fed continuously during the ice-covered period, although at a much lower rate than during the summer season. No somatic growth could be detected during the ice-covered winter period and the condition factor of both species significantly declined, suggesting that the winter feeding rates were similar to or below the maintenance requirements. Also, the species richness and diversity of ingested prey largely decreased from summer to winter for both fish species. The winter diet of Arctic charr <20 cm was dominated by benthic insect larvae, chironomids in particular, and Gammarus lacustris, but zooplankton was also important in December. G. lacustris was the dominant prey of charr >20 cm. The winter diet of brown trout <20 cm was dominated by insect larvae, whereas large-sized trout mainly was piscivorous, feeding on juvenile Arctic charr. Piscivorous feeding behaviour of trout was in contrast rarely seen during the summer months when their encounter with potential fish prey was rare as the small-sized charr mainly inhabited the profundal. The study demonstrated large differences in the ecology and interactions of Arctic charr and brown trout between the winter and summer seasons.     

Winter feeding of ptarmigan (<Emphasis Type="Italic">Lacopus lacopus</Emphasis>, Galliformes,Tetraonidae) in Yakutia

This paper presents the results of long-term studies on winter feeding of ptarmigan in Yakutia. This territory of the species habitat is characterized by the longest snow period and low ambient temperatures. Like in the predominant part of the range, the basis of winter feeding of birds is made up here of the vegetative parts of willow and birch. The period of winter feeding lasts 230–250 days in individuals of the northern populations and 170–180 days in individuals of the southern population. It was found that the preference for birch by ptarmigan changed to a preference for willow with advancement to the north and to the mountains. In addition to birch and willow, the diet of the birds includes up to 23 plant species. Among them, horsetail, chosenia, and larch can serve as the main food due to both biotic factors (the presence of animal excavations) and abiotic factors (thin snow cover, long-term severe frosts). In severe frosts, ptarmigans mainly feed on the ground using almost all the plants including those they do not prefer in warmer days. Two peaks of the craw fullness were observed in birds at average daily air temperatures below–50°C, and four peaks were noted in warmer days. The first peak is obviously due to the need to be in shelter for most of the daytime.     

Ecological role of reindeer summer browsing in the mountain birch (<Emphasis Type="Italic">Betula pubescens</Emphasis> ssp. <Emphasis Type="Italic">czerepanovii</Emphasis>) forests: effects on plant defense,litter decomposition,and soil nutrient cycling

Mammalian herbivores commonly alter the concentrations of secondary compounds in plants and, by this mechanism, have indirect effects on litter decomposition and soil carbon and nutrient cycling. In northernmost Fennoscandia, the subarctic mountain birch (Betula pubescens ssp. czerepanovii) forests are important pasture for the semidomestic reindeer (Rangifer tarandus). In the summer ranges, mountain birches are intensively browsed, whereas in the winter ranges, reindeer feed on ground lichens, and the mountain birches remain intact. We analyzed the effect of summer browsing on the concentrations of secondary substances, litter decomposition, and soil nutrient pools in areas that had been separated as summer or winter ranges for at least 20 years, and we predicted that summer browsing may reduce levels of secondary compounds in the mountain birch and, by this mechanism, have an indirect effect on the decomposition of mountain birch leaf litter and soil nutrient cycling. The effect of browsing on the concentration of secondary substances in the mountain birch leaves varied between different years and management districts, but in some cases, the concentration of condensed tannins was lower in the summer than in the winter ranges. In a reciprocal litter decomposition trial, both litter origin and emplacement significantly affected the litter decomposition rate. Decomposition rates were faster for the litter originating from and placed into the summer range. Soil inorganic nitrogen (N) concentrations were higher in the summer than in the winter ranges, which indicates that reindeer summer browsing may enhance the soil nutrient cycling. There was a tight inverse relationship between soil N and foliar tannin concentrations in the winter range but not in the summer range. This suggests that in these strongly nutrient-limited ecosystems, soil N availability regulates the patterns of resource allocation to condensed tannins in the absence but not in the presence of browsing.     

Interannual variation in the diet of non-breeding male Antarctic fur seals, <Emphasis Type="Italic">Arctocephalus gazella</Emphasis>, at Isla 25 de Mayo/King George Island

The diet of non-breeding male Antarctic fur seals, Arctocephalus gazella, was investigated at Stranger Point, King George Island, through the analysis of scats during three consecutive summer seasons (1996, 1997, 1998). Overall, fish and krill were the most frequent prey occurring, respectively, in an average of 82.9% and 78.8% of samples (n = 131), followed by penguins (22.8%) and cephalopods (17.8%). Myctophids constituted almost 90% of the fish predated, with Electrona antarctica and Gymnoscopelus nicholsi being the most abundant and frequent species consumed. All fish taxa identified were krill feeding species suggesting that seals foraged mainly on a krill and a fish community associated with krill aggregations. However, a seasonal change was observed in the relative proportions of the different prey taxa, with a progressive decrease with time in the occurrence of krill and a concomitant increase of fish, penguins and squid. Possible influence of the strong 1997/98 ENSO event is discussed.     

Food habits of genetically identified pine marten (<Emphasis Type="Italic">Martes martes</Emphasis>) expanding in agricultural lowlands (NW Italy)

We assessed the diet of pine marten (Martes martes) expanding in the heavily human-altered agricultural plain of the River Po, northern Italy. Between February 2008 and November 2009, surveys were carried out twice a week during seasonal sampling sessions of three to four consecutive weeks. To distinguish the faecal samples from those of sympatric carnivores, a polymerase chain reaction-restriction fragment length polymorphism method was applied. The availability of small mammals was assessed by the analysis of 59 barn owl (Tyto alba) pellets. A total of 109 pine marten faeces were analysed. Its diet consisted of fruit, rodents, lagomorphs and birds. Seasonal variation occurred for fruit, which prevailed in summer, and rodents, which were more preyed upon in autumn. In winter, the diet of the pine marten was almost totally based on vertebrates, and lagomorphs were the main source of protein in summer. Use of small mammals differed significantly from their availability, voles, particularly bank vole Myodes glareolus, being preferred to mice (Apodemus sp.) and rats (Rattus sp.). Medium-size mammals formed about 18% of pine marten diet, a value generally reported for high-latitude habitats. In agricultural areas, the pine marten proved to be an opportunistic predator, able to face the reduced availability of small mammals by preying upon medium-size prey and fruit.     

A comparison of the autecology of two seed-taking ant genera, <Emphasis Type="Italic">Rhytidoponera</Emphasis> and <Emphasis Type="Italic">Melophorus</Emphasis>

Members of the genus Rhytidoponera and, to a lesser extent, certain Melophorus spp. are keystone mutualists for the dispersal of seeds in the southwest of Western Australia, with important ramifications for the ecology and speciation of plants in this biodiversity hotspot. For this reason, it is important to understand the autecology of the relevant ant species and the way in which they interact with plant seeds. This paper addresses key aspects of the ecology of three such ant species, Rhytidoponera violacea (Forel), R. inornata Crawley and Melophorus turneri perthensis Wheeler. Data are presented on their geographic distribution, seasonality of foraging, diurnal activity, response to fire, nest site preference, nest structure, colony size, feeding habits, foraging response to seed availability, and seedling emergence from nests. The role of all three species as seed dispersers is confirmed, and all three species have ecologies that are well-suited for dispersal and survival of native plant seeds. Preservation of this interaction is important for the conservation of plants, and it is fortuitous that all three species are able to survive disturbance and return to rehabilitated areas. However, the smaller R. inornata, and to a lesser extent, the larger R. violacea, are vulnerable to invasive ant [Pheidole megacephala (Fabricius)] incursions. M. turneri perthensis is able to coexist with the invasive ant unless this is at high densities, probably as a result of its ability to forage during high temperatures when the invasive species is inactive.     

Gibbons under seasonal stress: the diet of the black crested gibbon (<Emphasis Type="Italic">Nomascus concolor</Emphasis>) on Mt. Wuliang,Central Yunnan,China

The diet of a habituated group of black crested gibbon (Nomascus concolor jingdongensis) was studied from March 2005 to April 2006 in the Wuliang Mountains, central Yunnan, China. Gibbons consumed 77 different plant species, one mammal-, two bird-, one lizard-, and two insect-species. Buds and leaves constituted 46.5% of the diet (21.0% vine leaves and buds, 19.2% tree leaves and buds, and 6.3% epiphyte leaves). Fruits, figs and flowers accounted for 25.5, 18.6 and 9.1% of the diet, respectively. There was marked seasonal variation in dietary proportions. Fruit varied from 0.3 to 82.7%; figs from 0 to 68.2%; tree leaves and buds from 1.5 to 83.3%; vine leaves and buds from 3.1 to 61.9%; and epiphyte leaves from 0 to 22.2% of the diet. Different food types dominated the diet in different months during the study period. The foli-frugivorous diet and extreme seasonal variation in the diet may be related to the harsh habitat of the study group.     

The diet of feral raccoon dog (<Emphasis Type="Italic">Nyctereutes procyonoides</Emphasis>) and native badger (<Emphasis Type="Italic">Meles meles</Emphasis>) and red fox (<Emphasis Type="Italic">Vulpes vulpes</Emphasis>) in Denmark

The raccoon dog (Nyctereutes procyonoides) is an East Asian Canid that has been introduced in Europe. Introduction of alien species is an increasing conservation issue. We examined the diet of a recently established raccoon dog population in Denmark by analysing stomach content in 249 carcasses collected in 2008–2016. Raccoon dog diet was compared to the diet of native badger (Meles meles) and red fox (Vulpes vulpes) in Denmark. The most common food for raccoon dogs were invertebrates (frequency of occurrence, FO 69%), small mammals (FO 68%), birds (FO 41%), fruits (FO 38%), amphibians (FO 36%) and carrions (FO 34%). The occurrence of invertebrates was highest during spring and summer, while fruits, cereals and carrions were eaten most often during autumn and winter. As expected, raccoon dog shared the major food categories with badger and red fox, but generally, it had a wider dietary niche. Overall, dietary overlap between raccoon dog and badger was 0.74 (Pianka index, O_jk). The dietary overlap with red fox was relatively high in all seasons, peaking in summer (O_jk 0.87) and dropping in winter (O_jk 0.79). Despite the dietary overlap between the alien racoon dog and native red fox and badger, the species may coexist due to partitioning of feeding habitats and/or because the red fox is limited by other factors, e.g. diseases and anthropogenic activities. The introduced raccoon dog seems to fit a dietary niche between badger and red foxes in human-dominated landscapes in north-western Europe.     

Feeding Behavior of <Emphasis Type="Italic">Liriomyza huidobrensis</Emphasis> (Blanchard) and <Emphasis Type="Italic">L. trifolii</Emphasis> (Burgess) Adults on Bean Leaves

The adult feeding behavior of Liriomyza huidobrensis and L. trifolii was studied in beans of the variety “Catarino.” The insects were placed on a bean leaf and its behavior observed and recorded on DVD for a period of 30 min. An ethogram was constructed based on the different behavior parameters that were identified. The time that each species used in each behavior parameter was registered and compared between the two species. When placed in the arena the two species behaved in a similar manner, although some differences were observed. The adaptation of the leafminers species to the “Catarino” bean variety under these experimental conditions and the possibility to use some behavioral parameters as indicators of the preference of these insects in relation to the host plant are discussed.     

Feeding selectivity of introduced hedgehogs <Emphasis Type="Italic">Erinaceus europaeus</Emphasis> in a dryland habitat,South Island,New Zealand

We describe the diet of introduced European hedgehogs Erinaceus europaeus (Linnaeus, 1758) in a New Zealand dryland system and provide the first quantitative analysis of food selectivity for this species. We also describe and compare the diets of nine hedgehogs and measure dietary overlap between these individuals. The most commonly eaten foods were beetles, including rare native species (in 94% of droppings), earwigs (92%), spiders (25%) and native skinks (14%). Remains of at least three skinks were found in one dropping. Earwigs and darkling beetles (Tenebrionidae) were the most preferred food types, and Hymenoptera and cylindrical bark beetles (Colydiidae) were least preferred. Consumption of most foods mirrored their availability. Most individuals’ diets conformed to the pattern seen at the population scale, with 21–54% of dry faecal mass derived from beetles and 13–39% from earwigs. One animal frequently consumed large amounts of fruit. Dietary overlap between pairs of individuals was high (mean Horn’s index, 0.84). This may be the result of limited opportunities to diversify in a very moisture-limited and low diversity habitat.     

Multiple host-ant use by the predatory social parasite <Emphasis Type="Italic">Phengaris</Emphasis> (=<Emphasis Type="Italic">Maculinea</Emphasis>) <Emphasis Type="Italic">arion</Emphasis> (Lepidoptera,Lycaenidae)

Phengaris (=Maculinea) arion is an endangered social parasite of Myrmica ants, and for a very long time was considered as specific to Myrmica sabuleti. Previous studies carried out in Poland suggested some discrepancies within this assumption, and therefore a much more intensive survey was undertaken. The host ant use of P. arion was studied at five sites in different types of biotopes in Poland, i.e. xerothermal grasslands where Thymus pulegioides was used as a larval food plant by the butterfly, and more or less sandy biotopes with Thymus serpyllum. Altogether nine Myrmica species were recorded, and considerable variation in species composition and density of nests was recorded. At four localities M. sabuleti proved to be the most common ant. A total of 529 Myrmica nests were examined, and only 20 of them contained larvae and pupae of P. arion. Host ants belonged to five different species, i.e. M. sabuleti, Myrmica scabrinodis, Myrmica schencki, Myrmica lobicornis and Myrmica hellenica. Only at one site (NE Poland) was a significant heterogeneity in parasitation rates among Myrmica species detected. M. lobicornis was the most often infested ant there, which may suggest local specialisation of the butterfly. Overall low parasitism rates may explain the vulnerability of P. arion in Central Europe but further studies are also necessary.     

Feeding habits of the cuttlefish <Emphasis Type="Italic">Sepia</Emphasis> <Emphasis Type="Italic">officinalis</Emphasis> during its life cycle in the Sado estuary (Portugal)

The importance of cephalopods in marine ecosystems is well recognized as they serve as important predators and prey in many food chains. During a 1-year period, cuttlefish were monthly sampled in five areas throughout the Sado estuary, and the stomachs of 445 individuals were examined. Significant changes in the diet according to their life stage were revealed, but similar food habits were presented by males and females. Juvenile individuals (the smaller ones with no visible distinct gonads) preyed mainly upon small crustaceans, while the immature ones (maturity stages I and II) had the most diverse diet with brachyurans as the major prey group. The mature individuals (maturity stages III and IV) showed a clear preference for larger crabs and fishes. Although the cuttlefish are known for their opportunistic feeding behaviour, a preference for some prey according to length and behaviour could be perceived during this study. Seasonal differences in the diet were mostly due to the variation of individuals according to their maturity stage during the year.     

Distribution and diet of 0-group cod (<Emphasis Type="Italic">Gadus morhua</Emphasis>) and haddock (<Emphasis Type="Italic">Melanogrammus aeglefinus</Emphasis>) in the Barents Sea in relation to food availability and temperature

Distribution of 0-group cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) in August–September 2005 and 2006 was mainly restricted to the Atlantic waters of the western and central areas of the Barents Sea. The main distribution of 0-group fish overlapped largely with areas of high biomass (>7 gm⁻² dry weight) of zooplankton. The copepod Calanus finmarchicus and krill Thysanoessa inermis, which are dominant zooplankton species in both Atlantic and boreal waters of the Barents Sea, were the main prey of 0-group cod and haddock. The main distribution, feeding areas and prey of 0-group cod and haddock overlapped, implying that competition for food may occur between the two species. However, though their diet coincided to a certain degree, haddock seems to prefer smaller and less mobile prey, such as Limacina and appendicularians. As 0-group fish increased in size, there seems to be a shift in diet, from small copepods and towards larger prey such as krill and fish. Overall, a largely pelagic feeding behaviour of 0-group cod and haddock was evident from this study.     

Factors Influencing Interannual and Intersite Variability in the Diet of <Emphasis Type="Italic">Trachypithecus francoisi</Emphasis>

Comparative studies of the diet of the same species in different habitats, and over the long term, are essential to understanding a species’ behavioral and ecological plasticity. Moreover, such studies can help researchers and managers evaluate a species’ capacity to cope with changes in habitat quality resulting from natural processes or human disturbance, which is important for developing conservation strategies. We compared dietary data for François’ langur (Trachypithecus francoisi) collected at Nonggang and Fusui Nature Reserves, Guangxi Province, China, over 2 separate study periods to evaluate interannual and intersite variation in diet. Young leaves were the preferred staple foods for langurs, whereas mature leaves and seeds served as fallback foods in response to seasonal shortage in the abundance of young leaves. Species composition of the diets and the percentage of feeding records for plant species varied between the 2 study periods. The langurs at both study sites fed selectively, and they did not base their diet simply on the abundance of plant species in the habitat. However, the plant species eaten by langur groups inhabiting the 2 different reserves were markedly different, and the top 10 food species eaten by the Fusui group showed no overlap with those eaten by the Nonggang group. The variation may be related to differences in forest composition resulting from different level of human disturbance. In summary, our results indicate that François’ langurs exhibit a comparable dietary pattern both temporally and geographically, but there is marked interannual and intersite difference in species composition of the langur diet.