The diet of Impala (Aepyceros melampus) in the Sengwa Wildlife Research Area, Rhodesia

The seasonal variation in the plant morphological part composition of the dict of Impala in the Sengwa Wildlife Research Area, Rhodesia, was determined by the analysis of rumen content samples from shot animals. The grass species composition of the diet was examined by microscopic identification of grass fragments found in the rumens. The seasonal variation in the dicotyledonous species composition of the diet was studied by direct observation of feeding animals. The protein contents of the rumen contents and faeces were used as measures of diet quality. In the wet season, grass was selected in preference to dicotyledonous plants, and grass leaf was the preferred plant part. In the late wet and early dry seasons, forbs were the principal food. The proportion of woody dicotyledons in the diet was at a maximum in the mid-dry season, when diet quality was at a minimum. Diet quality was directly related to the proportion of grass in the diet. Female Impala had a significantly higher quality diet than males, probably as a result of differential habitat selection.     

Diurnal activity patterns in hoverflies (Diptera, Syrphidae)

Abstract. 1. Time-budgets are constructed from censuses of hoverflies. Larger species spend less time in flight.
2. Most species are active under similar conditions of light intensity, but a shade-tolerant (Melanostoma scalare Fabr.) and a sun-loving species (Metasyrphus corollae Fabr.) were identified.
3. Large species become active (i.e. move, by flying or feeding) at lower temperatures than small ones, except M.scalare, which is tolerant to cool temperatures. This means that, M.scalare apart, the order of species appearing during the day is size-dependent, largest first.
4. Previous claims about the diel periodicity of syrphids can be reconciled by considering the importance of individual thermal balance.
5. Tolerance to low temperatures in small hoverflies is associated with feeding on anemophilous pollen; this may indicate a proline-fuelled flight.     

Diurnal activity patterns of coypu in an urban habitat

The ability of species to adapt to changing environmental conditions is a crucial need for surviving in human influenced landscapes. Especially non-indigenous species, which are flexible in their behaviour, may successfully enter and establish in new habitats. We compared the activity patterns of the invasive coypuMyocastor coypus (Molina, 1782) in an urban habitat in Germany with patterns observed in its native distribution range in South America as well as in areas, where it was introduced. In summer 1998 and winter 1999 a radio tracking study was carried out on six adult coypus, supplemented by count data on untagged animals. Whereas main activity in non-urban populations was recorded at night including dusk and dawn, coypus in the urban habitat were active during the day and early evening. We never observed animals between midnight and dawn. This reversal of activity patterns is attributable to deposition of human food in the city area during the daytime.     

山西平陆越冬大天鹅日间行为模式

2011年12月至2012年2月和2012年11月至2013年1月,采用瞬时扫描法,对山西平陆黄河湿地越冬的大天鹅进行了日间行为时间分配和活动节律的研究。结果表明,大天鹅在越冬期的主要行为是静息、运动和取食,分别占全部行为比例的(40.5±1.4)%、(22.8±0.9)%和(18.2±0.8)%。在日间节律方面,大天鹅的取食行为呈现早晚双高峰,静息行为的高峰则出现在早上和中午。对不同地点的大天鹅的行为时间分配研究表明,大天鹅在两地的行为时间分配存在明显差异。其中,在干扰强度较大的三湾村,运动和争斗行为更多;在干扰较小的关家窝村,静息和警戒行为更多。在行为时间分配与温度变化关系的研究中,通过Pearson相关性分析发现,大天鹅的取食、运动和理羽行为与温度成显著正相关,静息和警戒行为与温度呈现显著负相关。     

Diurnal activity patterns of three heron species in Queen Elizabeth National Park,Uganda

Kasoma, P.M.B. 2000. Duirnal activity patters of three heron species in Queen Elizabeth National Park, Uganda. Ostrich 71(1): 127–130.

Observations of activities were carried out over 12 h periods on the Goliath Heron, Grey Heron and Great White Egret along the shores of Lake Edward and Kazinga Channel. Behaviour was classified into three major categories: foraging, loafing and other behaviour. For all three species, foraging went on throughout the daylight hours but the level was variable both in the dry and wet seasons and between species. For all three species, foraging basically consisted of standing-and-waiting. The Great White Egret spent more time foraging than the other two species. Overlap between species in foraging activity on an hourly basis was high during most hours of the day implying that ecological separation through temporal partitioning of daylight hours is negligible.     

Changes in miombo woodland cover in and around Sengwa Wildlife Research Area, Zimbabwe, in relation to elephants and fire

One of the consequences of impacts of elephants and fire on woodlands is a change in woody cover, which often results in major challenges for wildlife managers. Changes in miombo woodland cover in and around Sengwa Wildlife Research Area (SWRA) between 1958 and 1996 were quantified by analyzing aerial photographs. Woody cover in SWRA decreazed from 95.2% in 1958 to 68.2% in 1996, with a lowest mean of 62.9% in 1983. The annual absolute rate of woody cover change in SWRA increazed from ?1.1% per annum between 1958 and 1964 to a recovery of 1.6% per annum between 1993 and 1996, while the annual relative rate increazed from ?1.1% per annum between 1958 and 1964 to 3.3% per annum between 1993 and 1996. There was a strong negative correlation between elephant densities and woody cover in SWRA, suggesting that loss of woody cover was mainly due to elephants. Woodland recovery after 1983 was due to reductions in elephant populations through legal and illegal off‐take and reductions in fire frequency. Surrounding areas experienced less woody cover losses than SWRA, mainly due to tree removal by locals whose densities increazed after the eradication of tsetse fly in the 1970s.     

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.     

Diurnal activity in the Samoan flying fox,Pteropus samoensis

Speakman and co-workers suggested the diurnal Samoan flying fox, Pteropus samoensis, may be at risk of hyperthermia when flying during the day, particularly at high levels of insolation. We monitored activity of this bat and climate simultaneously at two different sites and four times of year in American Samoa. Flight activity varied significantly with time of day, between days, study sites and seasons. Out of the six data sets collected, the four with the highest mean levels of insolation showed a significant decrease in bat numbers with increasing temperature and sunlight. When each individual activity count was directly compared to the predictions of Speakman and co-workers'' biophysical model, 85 to 95% of bat flight activity was found to be in conditions the model suggested would not pose a risk of hyperthermia. This supports the suggestion that in extreme conditions the animals would not fly as they risked overheating. The 5 to 15% of counts in which animals were seen to fly in conditions the model predicted they should not may be explained by erroneous assumptions underlying the model predictions.     

Diurnal fluctuations in activity in the izard

During daytime, variations in several activities were observed in the izardRupicapra rupicapra pyrenaica Bonaparte, e.g. grazing, resting and other behaviour watching, moving, etc. The grazing was more prominent in the morning and afternoon, diminishing rapidly in the middle of the day, at which time the resting phase increased. Other activities usually remained at a constantly low level. Although the fluctuations were observed from one season to another, the time of their occurrence, and their magnitude, varied with the season, age, and sex of the izards. Our main concern in this study was to determine the possibility of determining the factors underlying the fluctuations in izard activity.     

Diurnal patterns in the spatial relationships between saithe, Pollachius virens, schooling in the wild

Six saithe, length 35 to 43 cm, were tagged with acoustic transmitters and individuals tracked for between 9 and 508 h during May 1989. The tagged fish were members of a schooling group and during the study, pairs of tagged fish were tracked simultaneously for periods ranging from 9 to 139 h. These data have been used to investigate the spatial relationships between individuals schooling in the wild. Distances between individuals showed a distinct diel pattern. Tagged fish were generally closer together during the day, than either at night or the periods of dawn and dusk. Those circumstances under which pairs of tagged fish could be shown to school together were investigated by analysing the differences in their swimming directions. Schooling was generally evident during the hours of daylight, although the degree to which fish schooled varied between pairs. The degree to which the fish schooled was also dependent upon distance between the tagged individuals. Schooling could be demonstrated for saithe within 20 m of each other during the day and within 10 m in two out of three pairs at night.     

Diurnal activity patterns and feeding ecology of the endemic geladas (Theropithecus gelada) in the Simien Mountains National Park,Ethiopia

Diurnal activity patterns and feeding ecology of geladas (Theropithecus gelada) in Chenek, Simien Mountains National Park, were studied from January 2010 to April 2010. Data were gathered for 7 days per month starting from early in the morning to dusk. The study site (1805 ha) was divided into five blocks and a total of 397 individuals were counted using simultaneous census method. One band with 21 individuals was selected as a study group and scan sampling was used to study their diurnal activity patterns and feeding ecology. Geladas dedicated significantly more time to foraging than to other diurnal activities. They spent the majority of feeding time foraging on grass, and allocated little time to feeding on leaves, shoots, and flowers. Geladas of all age classes devoted the least time to resting, and spent similar amount of time moving. The study band was observed to interact with people, and to steal food from tourists and local people. Raising local people's awareness of geladas ecology and behavior might be a necessary component in the species' successful management and conservation.     

Diurnal patterns of pollen emission in Ambrosia, Phleum, Zea, and Ricinus

Hourly measurements of pollen emission were made from cultivated plots of Ambrosia, Phleum, Zea, and Ricinus over the course of several pollination seasons as part of a study of pollen dispersion from known sources. A characteristic diurnal emission pattern was found for each genus. Ambrosia pollen emission normally begins an hour or two after sunrise, peaks a few hours later, and decreases through the afternoon. Phleum starts during the night, peaks about 2 hr after sunrise, and declines slowly through the day. Zea emits pollen fairly uniformly during the period from 2 hr after sunrise to about sunset, while Ricinus pollen was collected from several hours after sunrise to late afternoon with a peak in mid-morning. Daily patterns often vary from the seasonal mean in response to changing meteorological conditions.     

Diurnal and spatial patterns of Phytoseiidae in the citrus canopy

Phytoseiid mites were sampled in a grapefruit orchard at various times of the day to study their diurnal and seasonal distributions in the tree canopy. Samples were collected on 14, 20 and 28 October 1999 at 2 h intervals from 0600 to 2200 h. Similar samples were collected in a grapefruit orchard at 3 h intervals from 0600 to 2100 h on 9 and 16 March and on 17 and 24 August 2000 for phytoseiid mites. No differences in numbers of phytoseiid motiles were observed among the hours sampled in any of the three months. However, significant differences were observed in the number of phytoseiids per leaf based on location within the tree (eastern, western sides of the canopy or interior). Interior leaves collected in March and August 2000 had higher numbers of phytoseiids than exterior leaves taken from either the eastern or western sides of the tree canopy. Phytoseiids were more abundant in the March 2000 samples (mean = 1.10 phytoseiids/leaf) than in either October 1999 or August 2000 samples (mean = 0.16 and 0.19 phytoseiids/leaf, respectively). Prevalent phytoseiid species were Typhlodromalus peregrinus (Muma) (42.1%) and Iphiseiodes quadripilis (Banks) (50.4%) in October 1999, Typhlodromalus peregrinus (Muma) (76.2%) in March 2000, and Euseius mesembrinus (Dean) (54%) in August 2000.     

Diurnal patterns of dopamine release in chicken retina

The retinal dopaminergic system appears to play a major role in the regulation of global retinal processes related to light adaptation. Although most reports agree that dopamine release is stimulated by light, some retinal functions that are mediated by dopamine exhibit circadian patterns of activity, suggesting that dopamine release may be controlled by a circadian oscillator as well as by light. Using the accumulation of the dopamine metabolite dihydroxyphenylacetic acid (DOPAC) in the vitreous as a measure of dopamine release rates, we have investigated the balance between circadian- and light control over dopamine release. In chickens held under diurnal light:dark conditions, vitreal levels of DOPAC showed daily oscillations with the steady-state levels increasing nine-fold during the light phase. Kinetic analysis of this data indicates that apparent dopamine release rates increased almost four-fold at the onset of light and then remained continuously elevated throughout the 12h light phase. In constant darkness, vitreal levels of DOPAC displayed circadian oscillations, with an almost two-fold increase in dopamine release rates coinciding with subjective dawn/early morning. This circadian rise in vitreal DOPAC could be blocked by intravitreal administration of melatonin (10 nmol), as predicted by the model of the dark-light switch where a circadian fall in melatonin would relieve dopamine release of inhibition and thus be responsible for the slight circadian increase in dopamine release. The increase in vitreal DOPAC in response to light, however, was only partially suppressed by melatonin. The activity of the dopaminergic amacrine cell in the chicken retina thus appears to be dominated by light-activated input.