Some factors affecting the grazing behaviour of sheep in winter in New South Wales

The effects of weather conditions in winter on the grazing behaviour of sheep was studied on the Southern Tablelands of New South Wales. Minimum screen temperatures were in the range −7 to 9°C, maximum temperatures 5 to 18°C and wind speeds between 26 and 126 km per day. Most observations were restricted to days with little or no rain. Data were obtained from vibrarecorder charts.Night grazing began earlier the lower the temperature, but temperature only accounted for 35% of the variation in the time that grazing began at night. The time that the first grazing period began in the morning was later the shorter the day, and the lower the maximum and minimum temperatures. If the diurnal fluctuation in temperature was high, grazing started later; this suggests that the sheep could sense the sort of day temperatures that would occur. These variables accounted for 52% of the variation in time that grazing began.Total time spent grazing over 24 hours was also influenced by the temperatures during the day, and by the temperature and wind-run the day before. The amount of grazing done the previous day had no effect. In all, 58% of the variation in grazing time was accounted for by weather effects.     

Activity patterns and resource use by sheep and red deer grazing across a grass/heather boundary

Diet selection and activities of sheep and red deer grazing alone and together across a grass (primarily Lolium perenne/Agrostis capillaris ) and heather ( Calluna vulgaris ) boundary, between July and October, are described.
Throughout the experiment, both animal species had a much higher proportion of grass than heather in their diet. Time spent grazing on each type of vegetation was similarly greater on grass, and the bite rates of the animals were also more rapid on the grass than on the heather.
Red deer spent more time grazing per 24 hours than did sheep, with sheep grazing less during darkness hours than red deer. Total grazing time of both species did not decrease with decreasing daylength from July to October.
There were no consistent differences in the diurnal patterns of activity of sheep and red deer, with both species showing 2-3 large grazing peaks per day.
There were no consistent effects of mixing sheep and deer on their grazing behaviour and diet composition.     

Pair-association in twin lambs before and after weaning

Association between twin lambs before and after weaning and their association with their dam before weaning was observed in Dalesbred, Jacob, Border Leicester and Border Leicester × Jacob Lambs. There was no significant difference between breeds, but the females spent more time close to the ewe than the males. The proportion of close associations was less and intermediate associations were higher in twins of mixed sex. The major effect of weaning was an increase in pair-association for 2 days; by the third day, pairassociation had returned to pre-weaning levels. It is interesting that pair-association with non-castrated males increased after weaning.     

喀斯特生境中猕猴的活动节律和时间分配

2006年9月至2007年8月,在广西弄岗国家级自然保护区选择一群猕猴(Macaca mulatta)作为观察对象,采用瞬时扫描取样法收集相关的行为数据,以日活动节律和活动时间分配为切人点,探讨猕猴对喀斯特石山生境的行为适应策略.结果表明,猕猴的日活动节律表现为上午和下午的觅食高峰,中午进入长时间的休息期.这可能与白天...     

The daily pattern of autumn bird migration in the northern Sahara

The temporal pattern of migration by passerine birds during the night, and their arrival during the day at the Egyptian coast and in the northern Sahara Desert was investigated. The mean direction of nocturnal migration at the coast was south-southeast, while at all desert sites it was south-southwest.
Birds arrived at the Egyptian coast only during the second half of the night which is explained by the fact that no birds could have taken off from the Mediterranean Sea. At least some of the birds landed at the coast where they spent the day before taking off shortly after sunset. These birds passed the desert sites at the expected time of day assuming a ground speed of 18 m per second. However, the origin of the birds passing the desert sites early at night is unclear. They must either have spent the day in the desert north of the study sites or they had overflown the Egyptian coast in the afternoon without landing.
The landing of birds during the day at the desert sites was bimodal. This pattern of arrival is explained either by some birds having landed at the Egyptian coast in the early morning before continuing, or by deteriorating conditions later in the day during flight or when resting in the desert, that obliged them to seek shelter at the desert sites.
A correlation between the number of migrants observed during the night and the number of resting birds in the desert on the following day suggests that an unknown proportion of birds might regularly use an intermittent migratory strategy that includes rest periods by day when crossing the desert, whereas others might adapt a non-stop migratory strategy.     

Alterations in the grazing activities of cased caddisfly larvae in response to variations in predation risk and resource level

Flexible behavioral response to avoid encountering predators has never been reported in lotic, cased caddisfly larvae with low mobility. However, an earlier laboratory experiment found the growth of such a caddisfly species, Glossosoma sp., decreased in the presence of a predatory sculpin, Cottus nozawae. We conducted laboratory experiments to test whether Glossosoma responses to sculpin varied according to resource level and/or time of day. Lower periphyton biomass resulted in increased movement at any time of day, but was followed by decreased grazing success of Glossosoma in the morning when they were sampled. Although sculpins were active in the morning, evening and night but never in the afternoon, movements of Glossosoma were suppressed by sculpin stimuli only in the morning, when food intake of Glossosoma also decreased, regardless of periphyton biomass. Glossosoma reduced the risk of predation by sculpin by flexibly controlling its grazing activities during the most risky period of the day (i.e. morning). Even in the morning in the presence of sculpin, lower resource levels resulted in longer movement distances similar to those in predator-free conditions, suggesting that lower resource availability promotes predation risk in natural streams inhabited by predatory sculpin.     

Foraging behaviour of chick-rearing rhinoceros auklets Cerorhinca monocerata at Teuri Island, Japan, determined by acceleration-depth recording micro data loggers

Flight and diving activity of rhinoceros auklets Cerorhinca monocerata breeding on Teuri Island, Japan, were monitored during the summers 1999 and 2000 using miniaturized time-depth and acceleration recorders. Birds made 14.5 dive bouts per day of on average 15.4 min duration, which consisted of on average 16.2 dives of 12.1 m depth and 42.7 s duration. Birds made 13.8±7.3 flight bouts per day, which lasted on average 11.5±4.5 min. Daily total flight duration was 2.7±1.7 h (range 54 s–5.1 h) and the mean potential foraging range was estimated to be 87 km (maximum 164 km). Most birds stayed at the colony or rested on the water surface during the night. Rhinoceros auklets dived more actively in early morning and in late afternoon than during mid-day. Compared to results from studies of time allocation in other alcids species, rhinoceros auklets spent longer time flying (3.3 hd⁻¹) and resting on water (13.1 hd⁻¹), and less time diving (3.1 hd⁻¹) and staying at the colony (4.4 hd⁻¹). These foraging patterns are probably related to the nest attendance pattern of rhinoceros auklets, i.e. leaving the colony early in the morning, staying at sea all the day and returning to the colony in the evening to provision their chicks.     

Reduced diurnal temperature range does not change warming impacts on ecosystem carbon balance of Mediterranean grassland mesocosms

Daily minimum temperature (T_min) has increased faster than daily maximum temperature (T_max) in many parts of the world, leading to decreases in diurnal temperature range (DTR). Projections suggest that these trends are likely to continue in many regions, particularly in northern latitudes and in arid regions. Despite wide speculation that asymmetric warming has different impacts on plant and ecosystem production than equal‐night‐and‐day warming, there has been little direct comparison of these scenarios. Reduced DTR has also been widely misinterpreted as a result of night‐only warming, when in fact T_min occurs near dawn, indicating higher morning as well as night temperatures. We report on the first experiment to examine ecosystem‐scale impacts of faster increases in T_min than in T_max, using precise temperature controls to create realistic diurnal temperature profiles with gradual day–night temperature transitions and elevated early morning as well as night temperatures. Studying a constructed grassland ecosystem containing species native to Oregon, USA, we found that the ecosystem lost more carbon at elevated than ambient temperatures, but remained unaffected by the 3 °C difference in DTR between symmetric warming (constantly ambient + 3.5 °C) and asymmetric warming (dawn T_min = ambient + 5 °C, afternoon T_max = ambient + 2 °C). Reducing DTR had no apparent effect on photosynthesis, probably because temperatures were most different in the morning and late afternoon when light was low. Respiration was also similar in both warming treatments, because respiration temperature sensitivity was not sufficient to respond to the limited temperature differences between asymmetric and symmetric warming. We concluded that changes in daily mean temperatures, rather than changes in T_min/T_max, were sufficient for predicting ecosystem carbon fluxes in this reconstructed Mediterranean grassland system.     

Meals for two: foraging activity of the butterflyfish Chaetodon striatus (Perciformes) in southeast Brazil.

The banded butterflyfish (Chaetodon striatus) from the tropical and subtropical western Atlantic is a territorial, diurnal forager on benthic invertebrates. It is usually seen moving singly or in pairs, a few meters above the sea floor. We studied the foraging activity of C. striatus on rocky reefs in southeastern Brazil. This fish spent about 11 h and 30 min per day on feeding activities, and preferred colonies of non-scleratinian anthozoans over sandy and rocky substrata while foraging. The lowest feeding rates were recorded in the early morning and late afternoon, but we found no further differences between feeding rates throughout the day. We also found no differences between the feeding rates of paired and single individuals.     

The effect of training at a specific time of day: a review

This article focuses on physical performances after training at a specific time of day. To date, although the effect of time of day on aerobic performances appears to be equivocal, during anaerobic exercises, the effect of time of day has been well established with early morning nadirs and peak performances in the late afternoon. These diurnal rhythms can be influenced by several factors such as the regular training at a specific time of day. Indeed, regular training in the morning hours may increase the lower morning performances to the same or even higher level as their normal diurnal peak typically observed in the late afternoon by a greater increase of performance in the evening. However, regular training in the evening hours may increase the morning-evening (i.e., amplitude of the rhythm) difference by a greater increase of performance in the late afternoon. Therefore, adaptations to training are greater at the time of day at which training is regularly performed than at other times. Nevertheless, although modifications in resting hormones concentrations could explain this time-of-day specific adaptations, precise information on the underlying mechanisms is lacking.     

The effects of sire-breed,forage availability and weather on the grazing behavior of crossbred ewes

For 17 days, 30 non-pregnant, non-lactating crossbred ewes, six per sire-breed (Suffolk, Clun Forest, Dorset, Polypay and Border Leicester), were grazed together during daylight hours (approximately 06.00–21.00 h Pacific daylight time) in a 0.87-ha grass—clover pasture. For the remainder of each day, the ewes were penned indoors without access to feed and water. On 6 days they were observed throughout the grazing period, with individual locations and activities being recorded every 10 min.The daily grazing pattern consisted of intensive a.m. grazing until about 10.00 h and intensive p.m. grazing after about 16.00 h. Cool, cloudy days had less distinct grazing periods than warm, sunny days. Average time spent grazing was 9.23 h (4.11 h a.m. and 5.12 h p.m.), and the average times of a.m. stop and p.m. start were 10.23 and 14.59 h, respectively. Average distance traveled was 1.39 km (0.76 km a.m. and 0.63 km p.m.).Sire-breed had no effect on either grazing time or distance traveled. Weather had a greater apparent effect than forage availability on grazing time, but forage availability had a greater apparent effect than weather on distance traveled. Sire-breed groups (averaged over observation days) differed in their grazing-site preference.A ewe's a.m. and p.m. grazing times were not correlated, but time of a.m. stop and p.m. start were negatively correlated. Grazing time and distance traveled were only moderately correlated.     

Where Do Livestock Guardian Dogs Go? Movement Patterns of Free-Ranging Maremma Sheepdogs

In many parts of the world, livestock guardian dogs (LGDs) are a relatively new and increasingly popular method for controlling the impact of wild predators on livestock. On large grazing properties in Australia, LGDs are often allowed to range freely over large areas, with minimal supervision by their owners. How they behave in this situation is mostly unknown. We fitted free-ranging Maremma sheepdogs with GPS tracking collars on three properties in Victoria, Australia; on two properties, four sheep were also fitted with GPS collars. We investigated how much time the Maremmas spent with their livestock, how far they moved outside the ranges of their stock, and tested whether they use their ranges sequentially, which is an effective way of maintaining a presence over a large area. The 95% kernel isopleth of the Maremmas ranged between 31 and 1161 ha, the 50% kernel isopleth ranged between 4 and 252 ha. Maremmas spent on average 90% of their time in sheep paddocks. Movements away from sheep occurred mostly at night, and were characterised by high-speed travel on relatively straight paths, similar to the change in activity at the edge of their range. Maremmas used different parts of their range sequentially, similar to sheep, and had a distinct early morning and late afternoon peak in activity. Our results show that while free-ranging LGDs spend the majority of their time with livestock, movements away from stock do occur. These movements could be important in allowing the dogs to maintain large territories, and could increase the effectiveness of livestock protection. Allowing LGDs to range freely can therefore be a useful management decision, but property size has to be large enough to accommodate the large areas that the dogs use.     

The daily activity of the elephant in the Rwenzori National Park, Uganda

Eighteen elephants were followed individually in the Rwenzori National Park, Uganda for varying periods and their activity noted at 4-min intervals. Continuous data extending over 24 h or more were collected from seven of these elephants. About 75% of the total time was spent in feeding and about 75% of the feeding activity consisted of grazing or feeding at ground level. There were three feeding peaks, one in the morning, another in the afternoon and the third around midnight. The feeding rate tended to increase during the day. The proportion of the total feeding time spent in browsing increased in the dry season. Walking took place mainly at dusk. The principal sleeping period occurred during the small hours of the morning with a shorter rest period in the early afternoon. The elephants defaecated about eleven times in the 24 h and drank an average of 1–3 times. The rate of progress through the bush averaged 0–5 km/h. Comparisons are made with published data concerning the activity patterns of waterbuck and warthog in the Rwenzori Park and of elephants in the Tsavo National Park, Kenya.     

Ectoparasites: are they the proximate cause of cleaning interactions?

We tested the importance of ectoparasites in cleaning symbioses by comparing the activity of Caribbean cleaning gobies ( Elacatinus evelynae ) and of their clients during three daily periods (early morning, midday and late afternoon) in which ectoparasite availability varied naturally. Emergence from the benthos of gnathiid isopod larvae, the main target of cleaning goby predation, was higher at night, when cleaners are inactive, than during the day. Overall ectoparasite loads also tended to be higher on clients in the morning. This coincided with higher rates of visits to cleaning stations by client fish in the morning than at midday, but high rates of client visits were also recorded in the late afternoon. Clients were more likely to adopt stereotypical incitation poses, which increase the likelihood of being cleaned, in the morning than later in the day. Inspection bouts by cleaning gobies were longest in the morning. Cleaner and client behaviours therefore change predictably in response to natural diurnal variation in ectoparasite availability. These results add to a growing number of studies supporting the idea that cleaning symbioses are mutualisms dependent on ectoparasite removal.     

Daily variation in body core temperature using radio-telemetry in aluminium industry shift-workers

The aim of this study was to investigate the diurnal variation in core temperature in aluminium shift-workers exposed to hot ambient conditions. Core temperature was continuously recorded via an ingestible radio-telemetry thermistor in 29 shift-workers. Data from the morning, afternoon and night shifts were aggregated for each participant to obtain 24-h recordings during work duties. Complete data were obtained from 10 participants. Results showed that body core temperatures recorded in the afternoon (from 12:00 h to 20:00 h) were significantly higher (P<0.05) than in the late evening, night and early morning (from 21:00 h to 08:00 h). In addition, core temperature displayed a circadian variation with a mesor of 37.45 (±0.19) °C, an amplitude of 0.23 (±0.12) °C and an acrophase at 16:36 h (±3:37 h). The peak values of core temperature recorded at each hour of the day on the work site followed the same pattern with an acrophase in the early afternoon. In summary, our data showed that shift-workers present higher core temperatures in the afternoon than in the morning or during the night. In addition, it was not the work duration but the hour-of-day that triggered the variation in core temperature. This result partly explains previous observations that workers under heat stress have a higher probability of heat illness during daytime shifts than during the night shift, and suggests that special care should be given to the afternoon shift and to the end of the morning shift.     

α1-Adrenoreceptor activity does not explain lower morning endothelial-dependent, flow-mediated dilation in humans

Early morning reduction in endothelium-dependent, flow-mediated dilation (FMD) may contribute to the high incidence of sudden cardiac death at this time of day. The mechanisms underpinning diurnal variation in FMD are unclear, but potentially relate to a circadian rhythm in sympathetic nerve activity. We hypothesized that blockade of α(1)-mediated sympathetic nerve activity would act to attenuate the diurnal variation in FMD. In a randomized and placebo-controlled design, we measured brachial artery FMD in 12 participants (mean age = 26 yr, SD = 3) at 0600 and 1600 after ingestion of an α(1)-blocker (prazosin, 1 mg/20 kg body mass) or placebo. Arterial diameter and shear rate were assessed using edge-detection software. Heart rate and blood pressure were also measured. Data were analyzed using linear mixed modeling. Following placebo, FMD was 8 ± 2% in the morning compared with 10 ± 3% in the afternoon (P = 0.04). Blockade with prazosin led to a slight but nonsignificant increase in morning FMD (P = 0.24) and a significant (P = 0.04) decrease in afternoon FMD, resulting in no diurnal variation (P = 0.20). Shear rate did not differ in the morning or afternoon under either condition (P > 0.23). Blood pressure was lower following prazosin compared with placebo (P < 0.02), an effect that was similar at both times of day (P > 0.34). Heart rate and norepinephrine levels were higher in the afternoon following prazosin. These data indicate that α(1)-adrenoreceptor activity does not explain lower morning endothelium-dependent FMD.     

Temporal Variation in Cleanerfish and Client Behaviour: Does It Reflect Ectoparasite Availability?

We tested the importance of ectoparasites as the proximate cause of cleaning interactions by comparing the activity of Caribbean cleaning gobies (Elacatinus evelynae) and of their clients during three daily periods (early morning, midday, and late afternoon) in which ectoparasite availability varied naturally. Emergence from the benthos of gnathiid isopod larvae, the main target of cleaning goby predation, was higher at night, when cleaners were inactive, than during the day. As a result, overall ectoparasite loads on client fish tended to be higher in the morning. Inspection bouts by cleaning gobies were longest in the morning, but also at midday when ectoparasite availability on clients was lower. Client fish were observed at cleaning stations most often in the afternoon, when they harboured few ectoparasites, but they were more likely to adopt incitation poses, which increase the likelihood of being cleaned, in the morning than later in the day. Most cleaner and client behaviours therefore did not change predictably in response to natural diurnal variation in ectoparasite availability. Our study suggests that the ultimate and proximate causes of cleaning behaviour need not necessarily coincide.     

WINTER FEEDING ECOLOGY OF WIGEON ANAS PENELOPE AT THE OUSE WASHES, ENGLAND

Investigations on the feeding ecology of Wigeon were carried out in winter 1978–79 at the species' most important inland wintering habitat in Britain. The study area included 287 ha of grassland, about one-sixth of the Washes, which is grazed by cattle and sheep until late autumn. In winter the area is partly or fully flooded. The number of Wigeon increased to 11 200 in January but cold weather in February, with snow and frozen flood water, forced the birds to leave, only 600 staying in the reserve. In March up to 4000 birds were again present. The distribution of the population within the refuge depends on whether the habitat is dry pasture with only a few ponds, partly flooded, fully flooded or covered with snow and frozen flood water. Under dry or slightly wet conditions 98% of the Wigeon were grazing (October to January), while under partly flooded conditions (February and March) 42%, fed on water. With increasing water depth, upending was used by 13%, while 45% of the population moved to the barrier banks, grazing there in March. The feeding method can change within a few hours with increasing water depth. The diurnal activity pattern varies during the wintering period. A lower percentage of morning feeding occurred after flights back from feeding outside the refuge and under frozen conditions. The feeding activity was higher at mid-day with a slight decrease towards dusk. The average diurnal feeding activity was 71% (October to April), with a maximum of 90% in November. Wigeon feed diurnally and nocturnally. During a 24 h period in March they were foraging for 15 h 40 min; by day 81% of the time was spent feeding, while at night only 48%. Standing crop measurements showed that the biomass of green vegetation declined significantly outside enclosures due to Wigeon usage. Pasture land should be grazed at different intensities by cattle and sheep before the arrival of the ducks. Inland reserves should include such pasture together with some standing water where the birds are undisturbed. The use of inland pastures can compensate for the loss of coastal habitats.     

The influence of long-term estrogen treatments on daily plasma prolactin levels in ovariectomized rats

Prolactin levels were determined in the plasma of female rats from 4 to 54 days after ovariectomy or ovariectomy and treatment with a long acting polymer of estradiol, polyestradiol phosphate (PEP), or Silastic implants of crystalline estradiol-17β. Blood samples were withdrawn from indwelling aortic catheters in the morning (0900–1100) and afternoon (1500–1700). Both methods of estrogen delivery elevated plasma prolactin in the morning and afternoon compared to ovariectomized controls. However, the increases in the afternoon were significantly greater than those in the morning. The difference from ovariectomized controls and the morning-afternoon differences were maintained for 25–26 days in the polyestradiol phosphate-treated group whereas those differences in the group receiving the implants of estradiol were significant for the entire length of the experiment (54 days). In addition, there were periodic fluctuations in the morning and afternoon levels of prolactin in the estradiol implanted animals. It is suggested that the plasma prolactin response to estrogen varies with time of day, time after administration of estrogen and with the method of estrogen delivery.     

Contribution of diurnal and nocturnal insects to the pollination of Jatropha curcas (Euphorbiaceae) in southwestern China

Jatropha curcas L. (Euphorbiaceae) is being increasingly planted worldwide, but questions remain regarding its pollination biology. This study examined the contribution of diurnal and nocturnal insects to the pollination of monoecious J. curcas, through its floral biology, pollination ecology, and foraging behavior of potential pollinators. Nectar production of both male and female flowers peaked in the morning, declined in the afternoon, and rapidly bottomed during the night in all of their anthesis days. The diurnal visitors to the flowers of J. curcas are bees and flies, and the nocturnal visitors are moths. Flowers received significantly more visits by diurnal insects than by nocturnal insects. Through bagging flowers during night or day or both or exclusion, we compared fruit and seed production caused by diurnal and nocturnal pollinators. Both nocturnal and diurnal visitors were successful pollinators. However, flowers exposed only to nocturnal visitors produced less fruits than those exposed only to diurnal visitors. Thus, diurnal pollinators contribute more to seed production by J. curcas at the study site.