Habitat Use by Weddell Seals and Emperor Penguins Foraging in the Ross Sea, Antarctica

The only apex predators that live year-round at high latitudesof the Ross Sea are the Weddell seal and emperor penguin. Theseasonal distribution, foraging depths, and diet of these twospecies appear to overlap. What makes it possible for emperorpenguins and Weddell seals to co-exist at high latitude throughoutthe winter when other marine tetrapods apparently cannot? Bothspecies have similar adaptations for exploitation of the deep-waterhabitat, forage on the same species, and routinely make longand deep dives. Yet, despite these similarities, there is probablylittle trophic overlap between the adults of both species dueto geographical and seasonal differences in habitat use. Forexample, during the winter months while female emperor penguinsare ranging widely in the pack ice, adult seals are foragingand fattening for the upcoming summer fast, literally beneaththe feet of the male penguins. However, there is more extensiveoverlap between juvenile seals and adult penguins, and shiftsin prey abundance and/or distribution would likely affect thesetwo groups similarly. In contrast, juvenile penguins appearto avoid inter- and intra- specific competition by leaving theRoss Sea once they molt.     

At-Sea Associations in Foraging Little Penguins

Prey distribution, patch size, and the presence of conspecifics are important factors influencing a predator’s feeding tactics, including the decision to feed individually or socially. Little is known about group behaviour in seabirds as they spend most of their lives in the marine environment where it is difficult to observe their foraging activities. In this study, we report on at-sea foraging associations of little penguins (Eudyptula minor) during the breeding season. Individuals could be categorised as (1) not associating; (2) associating when departing from and/or returning to the colony; or (3) at sea when travelling, diving or performing synchronised dives. Out of 84 separate foraging tracks, 58 (69.0%) involved associations with conspecifics. Furthermore, in a total of 39 (46.4%), individuals were found to dive during association and in 32 (38.1%), individuals were found to exhibit synchronous diving. These behaviours suggest little penguins forage in groups, could synchronise their underwater movements and potentially cooperate to concentrate their small schooling prey.     

Emperor Penguins Breeding on Iceshelves

We describe a new breeding behaviour discovered in emperor penguins; utilizing satellite and aerial-survey observations four emperor penguin breeding colonies have been recorded as existing on ice-shelves. Emperors have previously been considered as a sea-ice obligate species, with 44 of the 46 colonies located on sea-ice (the other two small colonies are on land). Of the colonies found on ice-shelves, two are newly discovered, and these have been recorded on shelves every season that they have been observed, the other two have been recorded both on ice-shelves and sea-ice in different breeding seasons. We conduct two analyses; the first using synthetic aperture radar data to assess why the largest of the four colonies, for which we have most data, locates sometimes on the shelf and sometimes on the sea-ice, and find that in years where the sea-ice forms late, the colony relocates onto the ice-shelf. The second analysis uses a number of environmental variables to test the habitat marginality of all emperor penguin breeding sites. We find that three of the four colonies reported in this study are in the most northerly, warmest conditions where sea-ice is often sub-optimal. The emperor penguin’s reliance on sea-ice as a breeding platform coupled with recent concerns over changed sea-ice patterns consequent on regional warming, has led to their designation as “near threatened” in the IUCN red list. Current climate models predict that future loss of sea-ice around the Antarctic coastline will negatively impact emperor numbers; recent estimates suggest a halving of the population by 2052. The discovery of this new breeding behaviour at marginal sites could mitigate some of the consequences of sea-ice loss; potential benefits and whether these are permanent or temporary need to be considered and understood before further attempts are made to predict the population trajectory of this iconic species.     

Foraging ecology of Gentoo Penguins Pygoscelis papua at Macquarie Island during the period of chick care

The diet, diving behaviour, swimming velocity and foraging range of Gentoo Penguins Pygoscelis papua were studied at Macquarie Island during the breeding season in the 1993–1994 austral summer. Gentoo Penguins are considered to be inshore feeders, and at Macquarie Island the diet and estimated foraging ranges supported this. The diet consisted of 91.6% fish and 8.3% squid, by mass. The dominant prey taxa were the fish Gymnoscopelus sp. and Paranotothenia magellanica. A mixture of pelagic and benthic prey was consumed, with a greater proportion of benthic species occurring later in the season. The penguins exhibited a strong diurnal pattern in their diving behaviour. Deep diving (≥30 m) began near sunrise (03.00 h) and finished close to sunset (21.00 h). Diving at night was less common and very shallow (<10 m). Early in the breeding season, dive profiles indicated that birds were probably following vertically migrating pelagic prey through the water column and were foraging in waters over 100 m deep. Later in the season, more uniform, shallower depths were used, suggesting an increase in benthic foraging activity. These changes in dive pattern and depth were consistent with the habitat preferences of prey species found in the diet. Gentoo Penguins swam at 1.04 m per s and had a maximum potential foraging range of about 26 km for single-day trips. They tended to forage within 14 km of the colony, with a mean range of 5.4 km. This range encompassed the deep ocean habitat to the west and east of the island and a shallow area to the north.     

Group Size in Foraging African Penguins (Spheniscus demersus)

Diving synchrony was examined for varying group sizes of African penguins (Spheniscus demersus) travelling to their foraging grounds from their breeding islands. Groups of fewer than 12 birds always dived synchronously, whereas groups of more than 17 birds always dived asynchronously. Since travelling penguins do not dive deeply, large groups of birds can remain together irrespective of diving synchronization. Observations from boats showed that foraging penguins rarely occurred in groups of more than 17 birds. We suggest that groups of penguins that do not have synchronized dives cannot forage effectively, because foraging penguins dive deeply.     

Foraging trip duration increases for Humboldt Penguins tagged with recording devices

Marine animals equipped with data recording devices sometimes show changes in their foraging behaviour, which can indicate an adverse effect of the instrument. We attached time-depth recorders (TDRs) and radio-transmitters to study foraging behaviour in Humboldt Penguins Spheniscus humboldti and observed an increase in the duration of foraging trips. We suggest that further tagging of this endangered species be approached with caution since this increase in trip duration may negatively affect reproductive and foraging success.     

四川梅花鹿的昼夜活动节律与时间分配

1987 年2 月至2000 年9 月, 用直接观察法在四川省铁布自然保护区中先后对287 只四川梅花鹿的昼夜活动节律和时间分配进行了2 934 h 的观察。四川梅花鹿的昼夜活动具有明显的活动与休息相间出现的节律, 晨昏和午夜是其活动的高峰期, 白昼活动强度较低以休息反刍为主。不同季节其昼夜活动节律有较大的变化。春、夏、秋、冬4 季每天单位时间的平均活动频率分别为: 55.29 ±32.97 %、46.42 ±37.24 %、48.21 ±35.80 %、47.75±32.21 % , 季节差异不明显( F = 0.32 < F_o.o1 ) 。昼夜年平均每天约有52.07 %的时间在活动, 其中白昼活动仅占5.28 % , 而晨昏和夜晚的活动占46.79 %。影响时间分配比例的因素为: 鹿的年龄、性别、繁殖状态、食物资源、天气状况、人为干扰等。     

笼养大斑啄木鸟行为时间分配和活动节律

2011年6～8月,在北京市野生动物救护中心露天笼舍内,采用瞬时扫描法对笼养条件下的4只大斑啄木鸟(Dendrocopos major)行为时间分配和活动节律进行了研究,利用单因素方差分析来说明不同性别大斑啄木鸟间行为时间分配差异以及研究对象在日间不同时间段行为节律差异.结果显示,笼养条件下大斑啄木鸟的各种行为活动具有一定的时间分配特点和日行为节律.大斑啄木鸟的行为主要表现为休息和飞行走动,占全部行为的36.24％和26.96％,其次为觅食行为,占17.69％.除觅食、理羽和其他行为外,雌雄间行为时间分配差异不显著(P＞0.05).大斑啄木鸟昼间活动的高峰期出现在上午,中午有午休现象,日间行为节律明显.飞行走动、休息、理羽、跳跃行为的发生频次在雌雄间无显著差异(P＞0.05),而雄性觅食的发生频次显著地大于雌性的(P＜0.05).     

Rut-Induced Hypophagia in Male Bighorn Sheep and Mountain Goats: Foraging Under Time Budget Constraints

In polygynous ungulates, the rut imposes constraints on male time budgets that generate a trade‐off between maintenance and reproduction, leading to a reduction in time spent foraging. As mating activities can incur substantial somatic costs, males are expected to spend their ‘non‐rutting’ time recovering during the breeding season. If the diminution in time allocated to foraging by males is only a consequence of time budget constraints, males should keep a similar ratio of time spent foraging to lying to that observed in the pre‐rut, leading to an overall reduction of these two activities (the ‘foraging constraint’ hypothesis). Alternatively, if males adopt an energy‐saving strategy, they should limit energy expenditures by reducing foraging but not lying time, as the energy gains of forage intake may not meet the basal energetic requirements, especially in northern and temperate regions (the ‘energy‐saving’ hypothesis). Here, we contrast these two hypotheses by comparing individual daily time budgets of marked adult bighorn sheep rams (Ovis canadensis) and male mountain goats (Oreamnos americanus) during the pre‐rut and the rut. Concordant results for both species support the ‘foraging constraint’ hypothesis, as sexually‐active males reduced time spent foraging and lying from the pre‐rut to the rut because of an increase in time spent in mating‐related activities. Bighorn sheep rams also increased time spent foraging when not engaged in mating tactics, providing further support for a ‘maximisation’ of energy intake in the absence of reproductive opportunities. Because there are also known physiological changes that occur during the rut which may cause appetite suppression, for example to produce metabolic compounds linked with olfactory communication (the ‘scent‐urination’ hypothesis) or to cope with increased burden of parasites (the ‘parasite‐induced anorexia’ hypothesis), further research should aim at simultaneously testing these current hypotheses to better understand rut‐induced hypophagia and its effects on the life histories of male ungulates.     

The diet of Emperor Penguins Aptenodytes forsteri in Adelie Land, Antarctica

This first quantitative study of the diet of Emperor penguins is based on 29 stomach contents collected with a water off-loading method in Adelie Land. The Emperor is largely ichthyophagous (65% by number and 95% by weight) and feeds extensively on small nototheniids (97% of the fish are 40–125 mm in overall length). These results and data on meal size and feeding frequency of the chick suggest that Emperors are off-shore foraging birds offering little competition for food with other sea-birds or mammals.     

不同饲养条件下海南坡鹿幼体春季昼间行为时间分配及活动节律

2003 年2 月至4 月间, 在海南甘什岭自然保护区采用瞬时扫描取样法对10 头海南坡鹿幼体昼间行为时间分配和活动节律进行了初步研究。结果表明: 坡鹿幼体昼间行为时间分配中摄食、卧息和反刍占有较大的比例;人工圈养和半散放条件下摄食、卧息、反刍、站立和运动行为的昼间时间分配差异性显著( P < 0.01), 半散放条件下幼鹿每天用于摄食和运动的时间比人工圈养的多, 而用于卧息、反刍和站立的时间较少, 其余行为时间比较接近; 在昼间活动节律方面, 圈养条件下摄食有3 个高峰期(09:00～10:00, 11:00～12:00, 16:00～18:00) , 卧息有2 个高峰期(10:00～11:00, 13:00～16: 00) ; 半散放条件下没有明显的摄食高峰期, 主要原因是大部分时间花费在食物的搜索和处理上, 而其卧息高峰出现在14:00 以后。     

Foraging behaviour of Magellanic Penguins during the early chick‐rearing period at Isla de los Estados,Argentina

Studies of the at‐sea distribution and trophic ecology of penguins are essential to understand their role in the broader marine food web. Magellanic Penguins Spheniscus magellanicus have a wide distribution and their foraging behaviour varies across breeding sites and between sexes, among others. In this study, we characterized the at‐sea areas, the diving strategies and the relative trophic level of Magellanic Penguins breeding at Isla de los Estados, Argentina, during the early chick‐rearing period. In addition, we quantified the interannual, sexual and individual variability in those parameters during three breeding seasons (2011–2013) using devices recording position and dive depth, and obtained blood samples for stable isotope analysis. During the early chick‐rearing period, Magellanic Penguins showed small differences between the sexes in their foraging behaviour and large overlap in the at‐sea areas used, suggesting no intraspecific variation between sexes. Although there was interannual variability in the foraging behaviour and the trophic level of the penguins, most of the studied nests managed successfully to raise both chicks during the first stage of the breeding cycle (guard stage). The foraging ecology of Magellanic Penguins from this colony was comparable with results of past studies at other breeding colonies. This study contributes to the identification of important at‐sea areas for Magellanic Penguins at the southern edge of their distribution and also to the identification of possible threats in the study area such as interaction with fisheries.     

扎龙湿地白鹤春季停歇地昼间行为时间分配及活动规律

在2004年4～5月,采用瞬时扫描取样法对扎龙国家级自然保护区林甸芦苇沼泽区的野生白鹤(Grusleucogeranus)在春季迁徙停歇地的昼间各种行为进行了研究。结果表明,在整个观察时期内白鹤各种行为具有较强的规律性,活动时间分配比例为:觅食31%、游走27%、静栖19%、警戒17%、修饰6%。白鹤觅食行为在一天中有两个高峰,分别为早晨和黄昏;游走行为基本上与觅食行为呈正相变化,并且几乎每个游走高峰及低潮相应地伴随着觅食的高峰和低潮;由于渔民清晨下苇塘收鱼和放牧,在5:30～6:30和6:30～7:30两个时间段警戒行为比例最高;静栖行为基本与游走及觅食行为呈负相关,对比发现,静栖行为比例低于觅食行为,与笼养鹤类的情况存在一定的差异,原因可能是食物丰富度影响了野生状态下行为的时间分配;修饰行为所占比例较小,是由于修饰行为是非主要行为,其发生是随机的。天气状况对白鹤数量变化有一定影响,阴雨和大风天气,白鹤数量明显减少,鹤群转移。与正常天气情况相比,阴雨和大风对白鹤觅食、静栖和游走行为时间分配影响显著(P阴雨=0·000<0·05,P大风=0·000<0·05),觅食时间缩短,游走行为减少,静栖时间变长。     

Sleeping Cave Selection,Activity Pattern and Time Budget of White-Headed Langurs

We describe the activity patterns and time budgets of white-headed langurs that were confined to about 4 km² of Longlin habitat in Fusui County, Guangxi Province, China. Between February and December 1996, we observed 6 langur groups monthly via group focal sampling and continuously recording the behavior of a focal group. Our results indicate that the langur groups selected stone caves on cliffs as sleeping sites. The daily activity pattern outside caves had 8 stages: (1) leaving the cave in the early morning; (2) moving and resting; (3) morning feeding; (4) moving a long distance; (5) resting at noon; (6) afternoon feeding; (7) moving back to the cave, and (8) entering the cave. Over the year, langurs spent a daily average of about 11.5 h outside caves and about 12.5 h inside caves. Moving accounted for 7% (spring), 7% (summer-autumn) and 13% (winter) of the time budget, and langurs spent 9% (summer-autumn) and 14% (spring) to 20% (winter) of their time feeding. Resting accounted for 79% of the time budget in spring, 84% in summer-autumn, and 57% in winter. Sunbathing only occurred in winter and accounted for about 10% of the time budget. One-way ANOVA and multiple range tests demonstrated that time budgets differed significantly among seasons. Langurs spent significantly more time feeding and moving in winter than in spring and summer-autumn, but significantly less time resting in winter than in spring and summer-autumn.     

笼养蓝冠噪鹛行为节律和时间分配研究

为了解笼养蓝冠噪鹛Garrulax courtoisi的行为节律和时间分配,2015年1—12月,采用全天瞬时扫描法,在南昌动物园对人工饲养的8只蓝冠噪鹛各种行为节律及时间分配进行了研究。结果表明,蓝冠噪鹛各种行为在全年的变化趋势不尽相同,繁殖期营巢、交配、卧巢、孵卵和育雏这5种繁殖行为增加,繁殖期结束,休息明显增加;全年中觅食的时间分配最高,为36.37%,其次为飞行(24.54%)、理羽(16.73%)、休息(7.75%)、社会行为(5.43%)、育雏(4.66%)、营巢(2.36%)、孵卵(1.92%)、卧巢(0.15%)和交配(0.01%)。单因素方差分析结果显示,除交配以外,其他行为的时间分配在繁殖期不同阶段的差异均有高度统计学意义(P0.001)。不同时期蓝冠噪鹛行为节律和时间分配反映了其生活史不同时期的相应需求,本研究结果可为蓝冠噪鹛人工饲养和野生种群行为研究提供参考。     

Time Budget and Activity Patterns of Oncilla Cats (Leopardus tigrinus) in Captivity

Researchers have reported on the diet of Leopardus tigrinus and ecological aspects, but studies of behavior are scarce. The aims of this study were to describe the time budget and activity patterns of 10 captive Leopardus tigrinus individuals. The group had an activity budget of 66% resting, 20.66% moving, 6.08% vigilant, 3.12% feeding, and 4.14% other activities during 720 hr of observations. The activity budgets of the males and females did not differ significantly; however, males ate more than did females. The nonhuman animals spent more time resting during the day than during the night. Moving, socializing, maintenance, and vigilance showed statistically higher mean values at night. Group analysis of the temporal pattern of behavior showed bimodal peaks. Activity levels were high from 5 a.m. to 6 a.m. and decreased through the day only to peak again at 7 p.m. Stereotypic pacing peaked at dawn and at dusk. Patterns of vigilance, feeding, and maintenance were also determined for the group during a 24-hr period. These results may be useful for the development of management plans and effective conservation strategies for captive cats.     

哺乳期圈养雌獐昼夜行为时间分配及活动节律

2014年7—8月,在浙江省富阳市獐养殖场采用瞬时扫描取样法对圈养条件下哺乳期雌獐昼夜行为时间分配及活动节律进行了调查研究。结果表明:1雌獐的日活动行为时间分配依次为卧息(59.01±2.93)%、走动(13.91±2.39)%、采食(10.60±0.74)%、梳理(7.76±1.10)%、反刍(2.84±0.66)%、站立(2.72±1.01)%、警戒(1.53±0.59)%、社会行为(1.26±0.54)%、排遗(0.36±0.22)%。2雌獐的昼间卧息时间极显著低于夜间(P<0.01),梳理时间显著低于夜间(P<0.05),而走动、采食、反刍、警戒和社会行为的时间极显著高于夜间(P<0.01),站立行为差异无统计学意义(P>0.05)。3一天中,雌獐的采食行为和反刍行为呈现双峰型的节律特征,走动、站立和梳理行为出现了3个高峰期,卧息和社会行为则呈多峰型,其中取食高峰后延迟1~2 h为反刍高峰。4卧息行为分别与采食行为和走动行为呈极显著的负相关关系,而采食行为与走动行为之间呈显著的正相关关系。总之,哺乳期圈养雌獐的日活动行为体现出明显的节律性,且大多数行为时间具有明显的昼夜差异。     

笼养绿尾虹雉繁殖季节的日行为节律和时间分配

2006年和2011年的3～6月,对宝兴蜂桶寨自然保护区笼养绿尾虹雉的日行为节律和时间分配进行了观察。结果表明:1)日行为节律:笼养绿尾虹雉的移动行为和取食行为表现出相同的变化规律,在一天中出现两个峰值;静栖行为的变化趋势与之相反;保养行为早晚较少,中午出现较多;繁殖行为和社会行为一天中均有发生;2)时间分配:一天之中行为比例最高的是静栖行为(54.18%±2.861%),其次是移动行为(34.29%±2.379%)、取食行为(5.51%±0.470%)、繁殖行为(3.68%±0.337%)和保养行为(1.64%±0.287%),最少的是社会行为(0.64%±0.106%);3)笼养绿尾虹雉的6种行为在个体间均表现出显著差异(P值均小于0.0001),而在两性间,只有取食行为表现出显著差异(t=-3.28,P=0.014),静栖行为、移动行为和社会行为个体之间无显著差异(t=-0.21,P=0.843;t=0.02,P=0.987;t=1.97,P=0.089),3种行为在不同时间段里有显著差异(t=-2.56,P=0.011;t=2.69,P=0.008;t=3.48,P<0.001),繁殖行为在一天中不同时间段里无显著差异(t=0.6222,P=0.534),保养行为在两性间和不同时间段里均无显著差异(t(sex)=-1.65,P=0.142;t(time)=-0.32,P=0.745)。