Seasonal Variation In Diet Research Articles

Do Eurasian otters Lutra lutra (L.) in the Somerset Levels prey preferentially on non-native fish species?

Eurasian otters Lutra lutra (L.) are known to be opportunistic, exploiting the most abundant prey available, however, there have been few studies of otter diet in lowland areas of Britain. The Somerset Levels and Moors, a coastal flood plain and marsh area of 64 000 ha in SW England, is an otter stronghold where a number of introduced, non-native fishes (common carp Cyprinus carpio, pumpkinseed Lepomis gibbosus, sunbleak Leucaspius delineatus) have been introduced, with the latter species occurring locally in high abundances. The present study aimed to determine whether otters of the Somerset Levels are preying on, and thus represent 'biological resistance' to, these non-native fishes. In 2004-2005, otter spraints (feces) were collected seasonally in areas of the Levels also subjected to fisheries surveys, and the data were used to determine diet composition and preferences. Otter diet was dominated by European eel Anguilla anguilla and threespine stickleback Gasterosteus aculeatus, and non-native species occurred relatively rarely (carp, sunbleak) or not at all (pumpkinseed) in the otter spraints. Seasonal variations in otter diet were observed, with birds notable for summer and sticklebacks for winter. Despite their relative prominence in the Somerset Levels, non-native fish species represented minor components of the otter's diet, a pattern also observed in Spain. In particular, the popular angling species (carp) was taken infrequently, but the species of high conservation interest (eel) was a preferred and common item in otter diet.

Feeding habits of the endemic tropical parthenogenetic lizard Cnemidophorus nativo (Teiidae) in a restinga area of northeastern Brazil

The population of Cnemidophorus nativo in the restinga of Guaratiba, Bahia State, Brazil, is carnivorous with a diet consisting predominantly of insect larvae and termites, which is similar to that of other cnemidophorines. The absence of seasonal variation in diet may be a consequence of the availability of termites throughout the year. The small size of the termites and the ease with which both juveniles and adults eat larvae independent of their length were probably the cause of the poor relationship between lizard body measurements and mean number and volume of prey consumed.

Food Habits of Finless Porpoises Neophocaena phocaenoides in Western Kyushu, Japan

We examined the stomach contents of 87 finless porpoises (Neophocaena phocaenoides) in the Ariake Sound–Tachibana Bay area and Omura Bay in western Kyushu, Japan, between 1987 and 1992. Fish (Gobiidae and Atherinidae) were the most numerous and most frequently occurring prey in Omura Bay, whereas both cephalopods (Octopodidae, Sepiidae, Sepiolidae/Sepiidae, and Loliginidae) and fishes (Clupeidae, Engraulidae, and Sciaenidae) were equally important in Ariake Sound–Tachibana Bay. Species compositions in the commercial catch differed between the 2 waters, suggesting that differences in prey availability may explain the geographical variation in diet. Finless porpoises in Ariake Sound–Tachibana Bay showed ontogenetic and seasonal variations in diet. The mean length at weaning was estimated to be 101 cm, corresponding to approximately 6 months of age. Calves fed on small-sized demersal fish and cephalopods. The predominant prey species for sexually mature individuals (including lactating females) consisted of konoshiro gizzard shad (Konosirus punctatus) and cephalopods. Seasonal availability of these organisms may be related to births in the fall–winter season in Ariake Sound–Tachibana Bay. Size-dependent prey selectivity was equivocal. Day–night difference in foraging time was not indicated by the index of stomach fullness.

Foot-and-Mouth Disease Vaccination in South Sudan: Benefit-Cost Analysis and Livelihoods Impact

A benefit-cost analysis of vaccination for foot-and-mouth disease (FMD) was conducted in an area of South Sudan, which due to chronic conflict, had been subject to large-scale humanitarian assistance for many years. The study used participatory epidemiology (PE) methods to estimate the prevalence and mortality of acute and chronic FMD in different age groups of cattle, and the reduction in milk off-take in cows affected by FMD. The benefit-cost of FMD vaccination was 11.5. Losses due to the chronic form of FMD accounted for 28.2% of total FMD losses, indicating that future benefit-cost analyses for FMD control in pastoral and agropastoral areas of Africa need to consider losses caused by chronic disease. Participatory epidemiological methods were also used to assess the importance of milk in the diet of Nuer agropastoralists, and seasonal variations in diet in relation to cattle movements and FMD outbreaks. Marked seasonal variation in diet included a 'hunger gap' period during which households were highly dependent on milk as their main source of food. Outbreaks of FMD occurred immediately before this period of milk dependency, with chronic losses extending through this period and affecting human food security. The paper discusses the need and feasibility of mass vaccination and strategic vaccination for FMD in South Sudan. The paper also discusses the value of combining conventional benefit-cost analysis with livelihoods analysis to inform disease control efforts and funding commitments in humanitarian contexts.

Feeding ecology of the Great Basin Rattlesnake (Crotalus lutosus, Viperidae)

Documenting variation in organismal traits is essential to understanding the ecology of natural populations. We relied on stomach contents of preserved specimens and literature records to assess ontogenetic, intersexual, temporal, and geographic variations in the feeding ecology of the North American Great Basin Rattlesnake ( Crotalus lutosus Klauber, 1930). Snakes preyed mainly on rodents, occasionally on lizards, and less frequently on birds; squamate eggs and frogs were rarely eaten. There was a positive relationship between predator and prey size. The best predictors of this relationship were prey diameter as a function of snake body length and head size, underscoring the importance of prey diameter for gape-limited predators such as snakes. Crotalus lutosus displayed ontogenetic, sexual, and seasonal variations in diet. Smaller rattlesnakes fed predominantly on lizards, whereas larger individuals mostly fed on mammals. Females fed on lizards more often than males. The proportion of mammals in the diet was highest during the summer, a temporal variation that may be related to behavioral shifts in the diel activity and prey selectivity of C. lutosus, and (or) to differential abundance of rodents between seasons. Great Basin Rattlesnakes also displayed geographic variation in feeding habits, with snakes from the Great Basin Desert eating a higher proportion of lizards than serpents from the more northern Columbia Plateau.

Deciphering seasonal variations in the diet and drinking water of modern White‐Tailed deer by in situ analysis of osteons in cortical bone

In situ carbon and oxygen isotope values for bioapatite were obtained from longitudinal slices of cortical bone from modern domesticated sheep and free‐range White‐Tailed deer. The analyses were obtained using an IR‐laser coupled to a GC‐IRMS interface. Ablation pits averaged 200 × 50 μm, making it possible to sample individual or small bundles of osteons. Cortical bone is remodeled along osteons throughout a mammal's life. Therefore, data at this scale can record seasonal variations in diet and drinking water during the adult stages of a mammal, whereas teeth provide may provide information about the juvenile years of a mammal. Average δ18O and δ13C values for the sheep from southwestern Ontario, Canada, were 14.0 and −16.1‰, respectively. No trend was observed in the isotopic composition of the sheep's osteons, consistent with its constant diet and water supply. The δ18O (14.2 to 16.6‰) and δ13C (−19.2 to −15.6‰) values of osteons from White‐Tailed deer from nearby Pinery Provincial Park, however, varied systematically and were negatively correlated. Oxygen isotope values of the osteons correlated well with changes in the δ18O values of the main water source for these deer: winter average, −10.7‰; summer average, −8.6‰. The variation in δ13C values of the osteons reflects changes in diet; summer diet consisted mainly of leafy C3 vegetation (−28.4‰), whereas winter diet comprised bark (−25.6‰), C4 grasses (δ13C, −12.7‰), and corn stalks and husks (−11.3‰).

Food habits of the sandpaper skate, Bathyraja kincaidii (Garman, 1908) off central California: seasonal variation in diet linked to oceanographic conditions

The stomachs of 130 sandpaper skates, Bathyraja kincaidii (Garman, 1908), were sampled from off central California to determine their diet composition. The overall diet was dominated by euphausiids, but shrimps, polychaetes and squids were also important secondary prey. A three-factor MANOVA demonstrated significant differences in the diet by sex, maturity status and oceanographic season using numeric and gravimetric measures of importance for the major prey categories. These three main factors explained more variation in diet than interactions between the factors, and season explained the most variance overall. A detailed analysis of the seasonal variation among the prey categories indicated that abundance changes in the most important prey, euphausiids, were coupled with seasonal changes in the importance of other prey. When upwelling occurred and productivity was great (Upwelling and Oceanic seasons), euphausiids were likely highly abundant in the study area and were the most important prey for B. kincaidii. As productivity declined (Davidson Current season), euphausiids appeared to decrease in abundance and B. kincaidii switched to secondary prey. At that time, gammarid amphipods and shrimps became the most important prey items and polychaetes, mysids and euphausiids were secondary.

Behavioural observations of foraging minke whales (Balaenoptera acutorostrata) in the outer Moray Firth, north-east Scotland

The minke whale (Balaenoptera acutorostrata) is a widespread, opportunistic species showing spatial and seasonal variations in diet according to local availability of prey. Although previous research has been conducted on the foraging strategies of this small rorqual whale, in terms of prey aggregation and assimilation, relatively little has been published on the foraging association of this species with coastal seabirds. Over the past five years, minke whales occurring along the outer coastline of the southern Moray Firth in north-east Scotland during the summer and autumn months have been recorded foraging in the presence of seabirds, such as kittiwakes (Rissa tridactyla), herring gulls (Larus argentatus), guillemots (Uria aalge) and shearwaters, which form dense feeding rafts at the water's surface. The formation of bird rafts notably occurs independently of the presence of B. acutorostrata, believed instead to be the successive result of prey concentrated at the surface by predatory schooling fish from below rather than by activities of the whales themselves. In this area of the North Sea, schooling mackerel (Scomber scombrus) constitute the most significant component of the summer fish biomass and are believed to perform the role of compacting targeted sandeel (Ammodytes spp.) prey into concentrated bait balls almost exclusively. The resulting ball of prey is consequently available to the foraging whale, which can be seen opportunistically utilizing successive bird rafts rather than expending unnecessary energy corralling the Ammodytes prey by traditional, active entrapment methods. The role of the mackerel in increasing both the rate and density of sandeel ball formation (as indicated by the presence and activity of associated bird rafts) is therefore thought to be very significant in this inshore Scottish location. Changes in oceanographic variables such as water temperature have been directly correlated with the migration of S. scombrus. The observed inter-annual variability in B. acutorostrata distribution in the outer Moray Firth may subsequently be related to the respective distribution and abundance of these migratory, pelagic fish species.

Ocean climate and prey availability affect the trophic level and reproductive success of the marbled murrelet, an endangered seabird

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 329:267-279 (2007) - doi:10.3354/meps329267 Ocean climate and prey availability affect the trophic level and reproductive success of the marbled murrelet, an endangered seabird Benjamin H. Becker1,2,*, M. Zachariah Peery1,3, Steven R. Beissinger1 1Division of Ecosystem Sciences, Department of Environmental Science, Policy and Management, 137 Mulford Hall No. 3114, University of California, Berkeley, California 94720-3114, USA 2Present address: Pacific Coast Science and Learning Center, Point Reyes National Seashore, Point Reyes Station, California 94956, USA 3Present address: 7544 Sandholdt Road, Moss Landing Marine Laboratories, Moss Landing, California 95039, USA *Email: ben_becker@nps.gov ABSTRACT: We investigated relationships between oceanographic processes, prey availability, diet and the reproductive success of the marbled murrelet Brachyramphus marmoratus (Alcidae), a federally threatened seabird. We predicted that cooler ocean conditions (which increase primary productivity in this eastern boundary upwelling system) should result in heightened prey availability and hence higher reproductive success for the murrelet. We also expected that murrelet diets should reflect those potential prey species that are most abundant during any given season or year. Oceanographic conditions were considered at 2 spatial scales: synoptic (Northern Oscillation Index, NOI; Pacific Decadal Oscillation Index, PDO; the North Pacific Index, NPI), and local (upwelling index, UI; sea surface temperature, SST; strength of the spring turnover). To infer seasonal and annual variation in murrelet diets in central California, we used stable isotope analyses of δ15N and δ13C in murrelet feathers and prey tissues during the pre- and postbreeding seasons of 1998 to 2002. Isotopic signatures of 10 species of potential prey clustered into 3 distinct groups (low, mid and high trophic level seabird prey). During 1999 to 2001, when more krill (low trophic level prey) were available, murrelet δ15N and trophic level were lower prior to breeding than after breeding, whereas pre- and postbreeding diets were similar during 1998 and 2002 when fewer krill were available. δ13C was always lower in prebreeding than postbreeding diets, which tracked availability of 13C enriched juvenile rockfish and market squid. Diet did not differ by sex for either isotope. Murrelet productivity (juvenile:adult ratios) was positively correlated with both rockfish and krill abundance. PDO, NOI, UI, spring turnover strength and NPI indices were unrelated to murrelet productivity and to prey abundances. Murrelet productivity was also positively related to the proportion of mid trophic level prey in postbreeding diets, and thus negatively related to the proportion of low and high trophic level prey consumed. Furthermore, productivity was markedly higher following the apparent 1998 to 1999 PDO regime shift to cooler conditions. These data suggest that cooler local temperatures support increased availability of krill and juvenile rockfish to murrelets, and that this improves murrelet reproductive success. KEY WORDS: Stable isotope · Marbled murrelet · Seabird · Diet shift · Brachyramphus marmoratus Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 329. Online publication date: January 11, 2007 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2007 Inter-Research.

Seasonal variation in the diet of citril finches Carduelis citrinella: are they specialists or generalists?

The seasonal variation of food selection in mountainous citril finches was studied in the Black Forest. citril finches show a strong seasonal variation in quantity and quality of food plants. From November to March, only a few plants have been observed as diet, namely seeds of the germander and the mountain pine (period of food restriction). From April to June, the seeds of a few key food plants such as the dandelion, common sorrel, vernal grass, and mountain pine gain special importance during breeding and the rearing period of the young (period of food specialization). Finally, from June/July to October, citril finches enter into a generalist period with a wide variety of seeds of herbs and grasses (period of food generalization). The changes in food selection are well adapted to the changing resource availabilities and climatic conditions of the Black Forest mountains. In direct comparison to other finches, pure mountain-dwelling species such as citril finches and Syrian serins show a clearly higher seasonal variability in food selection than do lowland species such as goldfinches, linnets, and greenfinches.

Diet of the “key herbivore” Diadema antillarum in two contrasting habitats in the Canary Islands (Eastern-Atlantic)

We analyzed the gut content of 30 sea urchins of the species Diadema antillarum which were collected seasonally over the course of two years from two different marine environments (barren grounds and grazing fronts) in the Canary Islands (Tenerife). Results show the influence of these two habitats on the diet of the sea urchin Diadema antillarum. No annual variations in diet were recorded; however we did find seasonal variations in diet in both barren and grazing front habitats. D. antillarum is mainly an herbivorous grazer but it also consumes invertebrates, especially in barren areas where seaweeds are scarce. Within the gut contents, filamentous algae were found in larger proportion than any other algal or animal group, independent of environment, month or year

Ontogenetic and seasonal variation in the diets of a Costa Rican leaf-litter herpetofauna

Ontogenetic and seasonal variation in diet was examined for 11 species of insectivorous forest-floor frogs and lizards from a lowland wet forest in north-eastern Costa Rica. Specimens were collected systematically over an entire seasonal cycle and represented individuals of all sizes. Individual prey items were removed from stomachs of preserved specimens, measured and identified. Ontogenetic shifts in prey size were pervasive. Ontogenetic shifts in prey composition were limited to four species; these were not the species with greatest range in body size, nor the species with the broadest diets. Small prey types (ants, mites, collembolans) decreased in representation and large prey types (roaches, orthopterans, millipedes) increased in importance over ontogeny; this could be because prey selection is based primarily on prey size or because of different prey preferences among age classes. There is little evidence for size-structure in this assemblage. There is no evidence that total availability of arthropod prey varies among seasons, but some evidence that preferred prey are less common in the wet season. Diet was similar between lizards and frogs. Lizards were more likely to have empty stomachs, but also greater stomach volume, than frogs; this indicates a difference in food-gathering strategies. Our study indicates strong similarity between frogs and lizards in diet despite enormous differences in physiology and behaviour.

Fish assemblage of a traditional fishery and the seasonal variations in diet of its most abundant species Wallago attu (Siluriformes: Siluridae) from a tropical floodplain

The fish assemblage of a traditional Kata fishery and the stomach contents of Wallago attu were studied over a period of one year from a large floodplain system in Bangladesh. A total of 19 species of fish and 2 species of shrimp were recorded. W. attu (9.7–17.8%), Mystus vittatus (6.0–11.3%), M. aor (5.0–12.1%), Amblypharyngodon mola (4.4–9.3%) and Mastacembelus armatus (3.5–10.5%) dominated the catch. W.␣attu occupied the top position in abundance throughout the year, followed by M. vittatus and M. aor. Bagridae, Siluridae and Cyprinidae were three major families that contributed respectively 21.0, 17.4 and 16.1% of the total catch. Considerable seasonality was observed in the abundance of different fishes. A total of 14 different prey items were recorded, belonging to three major groups (fish, prawn and plant matters). The fish fed on at least eight species of small fishes (A. mola, M. vittatus, M. cavasius, Puntius stigma, P. ticto, Puntius sp., Glossogobius guris, and Heteropneustes fossilis) and some other unidentified small fishes. Other major prey items were small prawn, fish and prawn remains, and macroalgae. A. mola was the most important food item, contributing 23.7% of the total amount of diet by weight and 19.9% by frequency of occurrence. A. mola was followed by unidentified small prawn (13.7%), M. vittatus (13.1%), and unidentified small fishes (8.8%) by weight and by unidentified small fishes (15.9%), fish remains (12.5%), and M.␣vittatus (12.3%) by occurrence. Of the major diet categories, fish contributed 74.3% of the total diet by weight and 80.9% by occurrence, prawn contributed 18.5% by weight and 11.0% by occurrence and plants contributed 7.2% by weight and 8.1% by occurrence. A. mola and small shrimps were positively selected by W. attu. We concluded that W. attu is a piscivorous predator with potential impacts on prey fish communities; we also hypothesized that a specialized food-web based on the Kata fishery exists in and around the Katas which is of particular ecological significance.

Diet of the spotted‐tailed quoll (Dasyurus maculatus) in eastern Australia: effects of season, sex and size

AbstractThe diet of spotted‐tailed quolls Dasyurus maculatus (Marsupialia: Dasyuridae) in the north‐eastern tablelands of New South Wales was investigated by faecal analysis. Medium‐sized mammals (500–6999 g) formed the bulk of the faecal content, in terms of both volume and frequency of occurrence. The most frequently consumed vertebrates were the greater glider Petauroides volans, rabbit Oryctolagus cuniculus, bandicoots Perameles nasuta and/or Isoodon macrourus, red‐necked pademelon Thylogale thetis, ringtail possum Pseudocheirus peregrinus, and brushtail possums Trichosurus vulpecula and/or T. caninus. Insects were also eaten frequently, but birds and reptiles occurred relatively infrequently in the diet. The seasonal variation in diet was marked, with insects and reptiles being consumed more frequently, and mammals less frequently, in summer than in winter. This seasonal pattern was also mirrored by the relative volumes of mammals and insects consumed. The results obtained here indicate that the spotted‐tailed quoll is an opportunistic predator, consuming a wide variety of taxa and apparently varying its diet to take advantage of short‐term fluctuations in prey abundance. The extremely high proportion of mammals in the diet identifies D. maculatus as a hypercarnivore, or meat specialist. The importance of tree hollow‐nesting mammals in the diet indicates that the preservation of hollow‐bearing trees should aid the conservation of D. maculatus. Future dietary studies of the species should sample over extensive time periods and involve concurrent monitoring of prey populations.

Seasonal variation of diet and food availability in a group of Sichuan snub‐nosed monkeys in Shennongjia Nature Reserve, China

We studied the diet and food availability of a group of Sichuan snub-nosed monkeys for 14 months (July 2003 to September 2004, except for February) in the Shennongjia Nature Reserve, China. This species is primarily a lichen eater, with lichens (Usneaceae) accounting for 43.28% of feeding records (n=3,452). Other food types in the diet were young leaves (28.71%), fruits or seeds (14.57%), buds (5.36%), mature leaves (3.51%), herbs (2.09%), bark (1.36%), and flowers (1.13%). The monkeys used 23 plant species. Their diet showed a complicated seasonal variation: the monthly diet varied from primarily lichens in November-April, to a mixture of leaves and lichens in May-July, to a mixture of fruits or seeds and lichens in August-October (the latter depended on annual fruit and seed availability). The proportion of fruits or seeds in the diet was negatively correlated with that of lichens, which suggests that the monkeys prefer fruits or seeds to lichens when all of these items are available. The fruit or seed availability varied greatly between the two study years. The proportion of lichens, young leaves, flowers, and fruits or seeds in the diet was positively associated with their availability. The monkeys appeared to be selective feeders. They preferred 10 tree species for plant parts, and nine tree species for lichens. The selection index of tree species for lichens was positively related to lichen coverage per branch on tree species, demonstrating that the monkeys preferred tree species with abundant lichens, as well as dead trees for lichens. The results suggest that dead-tree harvesting in the reserve could significantly reduce the quality of habitat for these monkeys, and should therefore be prohibited. Connus controversa, Cerasus discadenia, Salix willichiana, and Malus halliana should be conserved as top priority species because the monkeys preferred them for both their vegetative parts and the lichens that grow on them.

Feeding Habits of Common Snook, Centropomus undecimalis, in Charlotte Harbor, Florida

We examined the feeding habits, ontogenetic and seasonal diet variations, and predator size–prey size relationships of common snook, Centropomus undecimalis, in Charlotte Harbor, Florida, through stomach contents analysis. A total of 694 stomachs were extracted from common snook (300–882 mm standard length [SL]) during a 24-month period (March 2000–February 2002); 432 stomachs contained prey items. At least 37 prey taxa were identified, including 19 that had not been previously reported. Fishes made up 71% of the prey by number and 90% by weight. Three prey items made up almost 50% of the diet numerically—Lagodon rhomboides, Anchoa spp., and Farfantepenaeus duorarum. Seven species made up more than 60% of the diet by weight—L. rhomboides, Cynoscion nebulosus, Mugil gyrans, Bairdiella chrysoura, Synodus foetens, Orthopristis chrysoptera, and Mugil cephalus. An ontogenetic shift in prey preference was identified in adult common snook at around 550 mm SL. Smaller individuals (300–549 mm SL) ate more F. duorarum, palaemonid shrimp, cyprinodontids, and Eucinostomus spp. than did larger individuals (550–882 mm SL), which ate more S. foetens, ariids, and sciaenids. Significant, positive relationships between predator size and prey size were observed between common snook and L. rhomboides, O. chrysoptera, portunid crabs, and all fish prey combined. Prey size selection contributed to some seasonal differences in their diet. For example, in winter when L. rhomboides are abundant in the estuary and small in size (mean = 23 mm SL), common snook ate few individuals, but they consumed many during summer when larger L. rhomboides (mean = 51 mm SL) were available. In summary, common snook are opportunistic predators that feed on a wide variety of prey and exploit specific-sized prey that are abundant in their environment.

Ontogenetic changes in vertical distribution of an endemic amphipod, Jesogammarus annandalei, in Lake Biwa, Japan

We examined the seasonal variation in vertical distribution, gut fullness and diet of Jesogammarus annandalei, an endemic amphipod in Lake Biwa. The vertical distribution changed ontogenetically throughout the year and was restricted to depths with a water temperature < 12 °C. Newborn amphipods remained in the pelagic zone throughout the day while larger amphipods exhibited marked diurnal vertical migrations: individuals stayed on the lake bottom during the day and ascended to the pelagic zone at night. Gut fullness and contents of the migrating amphipods indicated that they fed upon plankton in the pelagic zone at night. Our results indicate that these migration patterns probably reduce the amphipod's predation risk from fish. As a result, J. annandalei may play an important role in the vertical translocation of material and energy in the Lake Biwa ecosystem.

Seasonal variation in food intake, physical activity, and body weight in a predominantly overweight population

To describe seasonal variation in food intake, physical activity, and body weight in a predominantly overweight population. A longitudinal observational study. Most of the study participants were recruited from a health maintenance organization (HMO) in central Massachusetts, USA. Additional individuals of Hispanic descent were recruited from outside of the HMO population to increase the ethnic diversity of this sample. Data from 593 participants, aged 20-70, were used for this investigation. Each participant was followed quarterly (five sampling points: baseline and four consecutive quarters) for 1-year period. Body weight measurements and three 24-h dietary and physical activity recalls were obtained on randomly selected days (including 2 weekdays and 1 weekend day) per quarter. Sinusoidal regression models were used to estimate peak-to-trough amplitude and phase of the peaks. Daily caloric intake was higher by 86 kcal/day during the fall compared to the spring. Percentage of calories from carbohydrate, fat and saturated fat showed slight seasonal variation, with a peak in the spring for carbohydrate and in the fall for total fat and saturated fat intake. The lowest physical activity level was observed in the winter and the highest in the spring. Body weight varied by about 1/2 kg throughout the year, with a peak in the winter (P<0.001 winter versus summer). Greater seasonal variation was observed in subjects who were male, middle aged, nonwhite, and less educated. Although there is seasonal variation in diet, physical activity and body weight, the magnitude of the change is generally small in this population. US National Heart, Lung and Blood Institute.

Seasonal Variations in Diet and Foraging Behavior of Ateles chamek in a Southern Amazonian Tropical Forest

I present data regarding the diet and feeding ecology of a spider monkey community at Lago Caiman in northeastern Bolivia. The community was highly frugivorous, only consuming significant amounts of folivorous material during times of relative fruit resource scarcity. Spider monkeys fed on parts of 86 plant species, but the majority of the diet comprised a few dominant fleshy fruit species that were available at temporally distinct periods across the year. Accordingly, I identified candidate keystone resources for the region and discuss the results with reference to previous studies on Ateles and the importance of considering keystone fruit resources in the management of forestry concessions.

Seasonal variation in the diet of Redshank Tringa totanus in the Odiel Marshes, southwest Spain: a comparison of faecal and pellet analysis

Capsule Redshank diet from southern Europe during migration shows spatial and seasonal variations. Aims To assess seasonal variation in Redshank diet at a major passage site, and to compare data derived from analysing pellets or faeces. Methods At the Odiel Marshes in 2001, pellets from spring migration (39), autumn migration (121) and midwinter (15) were analysed, together with faecal samples from autumn (84). Results The abundance of different invertebrate groups in pellets varied between seasons. In spring, Chironomus salinarius pupae and larvae dominated by volume, followed by Ephydridae larvae and the beetle Paracymus aenus. Polychaetes and molluscs dominated in autumn, and isopods in midwinter. In autumn, chironomid larvae, Mesembryanthemum nodiflorum seeds and Artemia cysts were relatively more abundant in faeces, whereas polychaetes, isopods, molluscs and cestode cysticercoids were more abundant in pellets. Harder and/or larger items were thus relatively more abundant in pellets than faeces. Pellet analysis gave more emphasis to mudflat prey, and faeces to saltpan prey. Conclusion Pellet and faecal analysis give different results for wader diet, and it is useful to combine the two methods. However, they show significant correlations both in diet range and rank abundance of prey items. Redshank diet shows much seasonal and spatial variation in southern Europe.