Foods of the silvereye (Zosterops lateralis; Aves) near Nelson,New Zealand

Abstract

The foods of 98 silvereyes (Zosterops lateralis) collected in winter from an orchard near Nelson, New Zealand, consisted of 61 different arthropods belonging to 14 orders. Commonest were Hemiptera in 54% of the birds, Diptera 53%, Coleoptera 34%, Lepidoptera 32%, and Araneida 23%. In addition earthworms, fruit, and seeds were eaten. Except for more beetles (Coleoptera) in males, the diets of the sexes were not significantly different.     

Isolation of microsatellite loci in the Capricorn silvereye,Zosterops lateralis chlorocephalus (Aves: Zosteropidae)

The Capricorn silvereye (Zosterops lateralis chlorocephalus) is ideally suited to investigating the genetic basis of body size evolution. We have isolated and characterized a set of microsatellite markers for this species. Seven out of 11 loci were polymorphic. The number of alleles detected ranged from two to five and observed heterozygosities between 0.12 and 0.67. One locus, ZL49, was found to be sex‐linked. This moderate level of diversity is consistent with that expected in an isolated, island population.     

Genetic monogamy in the absence of paternity guards: the Capricorn silvereye, Zosterops lateralis chlorocephalus, on Heron Island

We investigated the genetic mating system of a socially monogamous passerine bird, the Capricorn silvereye Zosterops lateralis chlorocephalus, on an island of the Great Barrier Reef. Therewere no cases of extrapair paternity (EPP) among 122 offspringfrom 53 broods detectable by minisatellite or microsatelliteDNA fingerprinting. Behavioral observations of paired birdsshowed that this was not a consequence of efficacious paternityguards and that females did not engage in extrapair copulation(EPC). Frequency of intrapair copulations was also low, withonly 14 cases observed during 199 hours of observations ofthe 11 focal pairs in the fertile periods of females, and thiswas consistent with anatomical features of the cloacal protuberancein males. In this population, young birds form life-time pairbonds soon after gaining independence but females are obviouslynot attempting EPC possibly to redress this early mate choice.This is despite the fact that they breed in high density witha synchronous start and asynchronous spread of laying in aprotracted season and males do not positively exhibit mateguarding behavior when females are fertile. Our results supporthigh fidelity of socially monogamous birds on islands and are consistent with the hypothesis that sexual selection is reducedwhere genetic variation in fitness is limited.     

The thermoregulatory limits of an Australian Passerine,the Silvereye (Zosterops lateralis)

(1) The thermal capabilities of Australian silvereyes (Zosterops lateralis, 11 g) were investigated both at low and high ambient temperatures (T_a) during the photophase and scotophase. (2). The peak metabolic rate (PMR) induced by helium–oxygen (79:21 %, He–O₂) exposure during the photophase was 15.64±1.55 mL O₂ g⁻¹ h⁻¹ at an effective lower survival limit T_a (T_pmr) of −39.7±6.1°C. (3). Above the thermoneutral zone (TNZ), metabolic rate, body temperature (T_b), and thermal conductance increased steeply, but they were able to withstand a T_a of 39°C. (4). Our study shows that silvereyes are able to tolerate an impressive range of T_a from about −42°C to at least +39°C and are able to produce enough heat to maintain a thermal difference between T_b and T_a of up to 80°C.     

Daily and seasonal activity patterns of the muskrat Ondatra zibethicus as revealed by radiotelemetry

Activity patterns of the muskrat Ondatra zibethicus L. were examined during summer and winter in Delta Marsh, Manitoba, Canada (50°11'N, 98°23'W). Animals exhibited intermittent activity throughout the day with a mean periodicity close to 6 h in both seasons. The 24-h activity pattern in summer was typically bimodal with major peaks occurring between sunset and sunrise. Muskrats were more diurnal in winter when maximal levels of activity occurred in late afternoon and early evening (1500–2000). Pronounced inter- and intra-individual variability in daily activity ensured continuous, or nearly continuous occupation of winter shelters by a variable number of muskrats, and thus enchanced microclimate stability. Daily variation in activity and weather were weakly correlated both summer and winter. Of the environmental variables tested, only photoperiod and wind speed in summer, and photoperiod and air temperature in winter correlated significantly with total time spent in lodge or burrow per day.     

Daily and seasonal activity in woodland ants

Summary Daily and seasonal foraging patterns are described for nine species of ants occupying a temperate zone woodland. Two common dominant species, Prenolepis imparis and Formica subsericea, are active at different times of day and during different parts of the year. They appear to be limited by physical factors (temperature and light, respectively) while the subordinate species show a wider tolerance of physical conditions. The subordinate species exhibit peak foraging periods which overlap in large part with most dominant species. This temporal pattern of species activity is discussed in relation to the competitive relationships within this ant guild.     

Daily and seasonal activity patterns of the dorcas gazelle,scimitar-horned oryx,north-African ostrich and canids in an arid habitat

North Africa's megafauna has developed behavioural adaptations to reduce energetic and fitness costs under harsh arid land conditions. Animal behaviour and activity patterns are difficult to study in the wild, but remote camera traps provide a solution to collecting data without the presence of a researcher influencing outcomes. Here, we report results from a study comprising over 20,382 camera-trap days during a 34-month period in Dghoumes National Park, Tunisia. We aimed to evaluate temporal activity patterns and their overlap and explore opportunities for niche partitioning. Our focal species were the reintroduced scimitar-horned oryx, north-African ostrich, dorcas gazelles and extant regional top-order predators, African wolf and red fox. We found differences in activity patterns between seasons across the focal species, with the most noticeable change being an increase in dawn activity from 1% to 33% between winter and summer for the red fox. Consequently, higher summer temperatures limit opportunities for temporal niche partitioning and push focal species towards dawn-time activity peaks resulting in higher intra-guild overlap values at dawn. Arid antelopes have physiological adaptations that enable them to better exploit ecological resources in hotter time periods than the carnivores, and this reduces inter-guild overlap during summer days.     

Daily and seasonal patterns of construction activity byOdontotermes latericius (Isoptera: Termitidae)

Summary Colonies ofOdontotermes ?latericius in the vicinity of Lusaka, Zambia, built their mounds primarily during the rainy season. Individual colonies began building some time before or after the beginning of the rains. Building usually ended before the end of the rains, but some colonies continued to build for some time after this. Occasionally a heavy rain after a period of dry weather caused numerous colonies to begin building again. There was no clear relation between building activity and other environmental factors.The pattern of activity within the rainy season varied greatly from colony to colony and year to year. Some colonies did no building during an entire season, and there was never a time when all colonies were active simultaneously. Except for a crude correlation of activity associated with rainfall the colonies seemed to be active at random with respect to each other. A colony sometimes remained continuously active for several months, but others were sometimes active for less than a day. A colony sometimes concentrated all its activity on one mound or chimney, but at other times activity shifted erratically from site to site. The structures built in one season usually were not used the following season. When building, the termites were active day and night, but usually were most active at night and least active on hot dry days.

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Résumé Dans les environs de Lusaka, Zambie, les colonies d'Odontotermes latericus construisent essentiellement leurs monticules durant la saison des pluies. Certaines colonies commencent la construction peu de temps avant ou après le commencement des pluies. En général, la construction cesse avant la fin des pluies mais quelques colonies continuent à construire pendant quelque temps après cette période. Habituellement une forte pluie après une période de sécheresse incide de nombreuses colonies à construire à nouveau.On ne trouve aucune relation évidente entre le comportement constructeur et d'autres facteurs d'environnement.Le schéma d'activité pendant la saison des pluies varie considérablement d'une colonie à l'autre et d'une année à l'autre. Certaines colonies ne construisent pas durant une saison entière et on n'observe jamais une période d'activité générale pour toutes les colonies. A part la corrélation évidente entre l'activité et les pluies, les colonies semblent actives au hasard chacune relativement aux autres. Une colonie peut rester active continuellement pendant plusieurs mois tandis que l'activité d'une autre peut durer moins d'un jour. Une colonie peut concentrer son activité sur une cheminée ou un monticule, tandis qu'à d'autres moments elle peut passer d'un emplacement à un autre de manière erratique. Les constructions édifiées durant une saison ne sont généralement pas utilisées durant la saison suivante. Pendant la construction, les termites sont actifs durant le jour et la nuit, mais habituellement ils sont les plus actifs durant la nuit et le moins pendant les jours chauds et secs.

     

Daily and seasonal variation in the activity of potential vector mosquitoes

In the course of season 2010 (May–September), three 2-day trappings of female mosquitoes were carried out at two sites in order to determine the daily activity of the common mosquito species (e.g. species from genus Culex, Aedes, Ochlerotatus, Anopheles, etc.) in the area. CDC light traps filled with CO₂ and placed at a height of 1 m were used to trap individuals, and were sampled every 2 h. A total of 19,604 female mosquitoes from 20 identifiable species were trapped: 7,549 at Sedlec and 12,055 at Kančí obora. The activity of the major species of mosquitoes in South Moravia differed throughout the course of the day. Calamity species of the genus Aedes and Ochlerotatus remained active throughout the day and night, but with different course. Aedes vexans, Ae. cinereus, and Ae. rossicus were most active in the late afternoon and highly active for most of the night. Ochlerotatus sticticus was captured most often in the afternoon, and its abundance decreased rapidly before sunset. The activity of Oc. cantans s.l. (Oc. cantans + Oc. annulipes) females varied little during the day and night. The daily activity for the main vectors of West Nile virus, Culex pipiens and Cx. modestus, were totally different from that of other species. Cx. pipiens females showed significant night activity, while Cx. modestus was most active in the evening. Nighttime activity was also observed in female mosquitoes of the genus Anopheles.     

Daily light regulates seasonal responses in the migratory male redheaded bunting (Emberiza bruniceps)

This study analyzed the role of day length in regulation of seasonal body fattening and testicular growth in a latitudinal Palaearctic-Indian migrant, the redheaded bunting (Emberiza bruniceps). When exposed to increasing photoperiods (hours of light: hours of darkness; 11.5L:12.5D, 12L:12D, 12.5L:11.5D, 13L:11D, 14L:10D, and 18L:6D) for 9-12 weeks, buntings responded in a photoperiod-dependent manner and underwent growth and regression cycle under photoperiods of > or =12 hr per day. Also, the response to a long photoperiod of birds that were held under natural photoperiods at 27 degrees N for 2 years was similar to those who arrived the same year from their breeding grounds ( approximately 40 degrees N), suggesting that the experience of higher amplitude day-night (light-dark, LD) cycles during migratory and breeding seasons were not critical for the subsequent response (initiation-termination-reinitiation) cycle. Another experiment examined entrainment of the circadian photoperiodic rhythm in buntings by subjecting them to T=24+/-2 hr LD-cycles with 8 hr photophase and to T=22 and 24 hr with 11 hr photophase. The results showed a reduction in critical day length under T=22 hr LD-cycle. In the last experiment, we constructed an action spectrum for photoperiodic induction by exposing birds for 4.5 weeks to 13L:11D of white (control), blue (450 nm), or red (640 nm) light at irradiances ranging from 0.028 to 1.4 W m(-2). The threshold light irradiance for photoinduction was about 10-fold higher for blue light, than for red and white lights. These results conclude that the daily light of the environment regulates the endogenous program that times seasonal responses in body fattening and testicular cycles of the redheaded bunting.     

Temporal changes in food resources,parental feeding and breeding success of Heron Island silvereyes,Zosterops lateralis chlorocephala

The influences of the temporal change in food supply on the parental feeding effort and breeding success of silvereyes,Zosterops lateralis chlorocephala, was investigated on Heron Island, Australia. Food supply (arthropods and figs) declined as the breeding season progressed. The parental feeding rate and growth of nestlings were lower when food supply was poor. When available, dominant pairs fed their young more figs and fewer arthropods than lower ranking pairs. Dominant pairs raised heavier young than lower ranking pairs when food supply was poor, while there were no significant differences between them when food supply was rich. When food supply was rich, pairs delivering greater amounts of arthropods reared nestlings better, whereas feeding more figs did not improve growth of nestlings. When food supply was poor, pairs spending a longer time at the nest reared nestlings better.     

Daily patterns of locomotor activity in a wandering spider

ABSTRACT. Cupiennius salei Keys., a lycosid spider, is night-active in its natural habitat in the highlands of Guatemala. Locomotor activity begins at dusk after several transitional states, each of which is correlated with a particular light level. Actograph measurements in controlled conditions (LD 12:12 or reversed cycles) show that the spiders begin walking immediately after dark. The activity maximum is reached within the first 3 h of the scotophase (though some spiders displayed additional lights-on activity in the first hour of the photophase). In DD, Cupiennius shows an endogenous activity rhythm with a mean period of 24.9 h (± 0.31, SE); typically during the first four to six cycles in DD the rhythm 'splits' into two components running at different frequencies. In LL (26 1x) the walking activity became arrhythmic. The results are discussed with reference to field and laboratory observations of Cupiennius behaviour and to the consequences for future physiological research with this species.     

Moult in captive partially migratory and sedentary Australian silvereyes ( Zosterops lateralis ) (Zosteropidae)

In this study, we describe and compare the duration and timing of post-breeding moult of primary and secondary wing feathers, tail feathers, wing coverts and body feathers in captive partially migratory and non-migratory Australian silvereyes (Zosterops lateralis). This study allowed us to follow individual birds through the course of their moult and record the progression of moult in two populations. Both groups of birds underwent a conventional (or basic) post-breeding moult. While all birds followed a similar pattern of feather replacement, differences were found in the timing and duration of moult between migratory and non-migratory birds. The migratory birds generally started their moult earlier in the year and completed it before the non-migratory birds. The migratory birds revealed an overall uniformity in the timing and duration of their moult, while the non-migratory birds showed a greater degree of variability between individuals.     

Annual activity patterns of anurans in a seasonal neotropical environment

Summary At Panguana, a study in the upper Amazon basin, 7 different aquatic breeding sites of anurans were investigated from Nov. 1, 1981 to Oct. 31, 1982. Rainfall in this area is seasonal. Only 20% of the total annual precipitation was maesured during the dry period, which lasted from mid-March until mid-September 1982. The reproductive periods of the species were highly affected by the rainfall distribution. Calling males and/or gravid females of 46 species were found during the study period. 37.0% of the anuran species were exclusively, and 43.5% predominantly, active during the rainy season. Plots of 100 m² were established at 6 aquatic sites in primary rainforest. A total of 2126 frogs was counted; 93.2% of these were made during the rainy season. A maximum of 378 individuals were found during one check in the plot at the permanent pond. At this site high concentrations of individuals and large choruses were found at the beginning of the rainy season. As soon as favourable temporary aquatic sites were established, reproductive activities decreased at the permanent pond and increased at temporary breeding sites.     

Habitat use,foraging behavior,and activity patterns in reproducing western tarsiers,Tarsius bancanus,in captivity: A managment synthesis

As the only obligatorily predatory primates, tarsiers are notoriously difficult to keep successfully in captivity. Here we report empirical and experimental results from a 5-year study of behavior and life history in captive Tarsius bancanus. Four reproducing adult tarsiers used space nonrandomly, preferring small-diameter vertical or near-vertical locomotor substrates at midlevel enclosure heights (1.2–2.1 m) for sleeping, scanning, and prey capture. The tarsiers were completely nocturnal, and spent 78% of the scotophase scanning, 13% sleeping, and 9% in prey capture and other activities. Only live crickets were eaten; prey capture rates were highest in the first hour after waking, but overall activity rates were highest later in the scotophase. Adult males and nonpregnant or lactating females ingested approximately 44.7–49.7 kJ/day. Growing and lactating individuals ingested approximately 84.4–94.1 KJ/day. An energetically conservative, sit-and-wait predatory strategy was employed, in which 88% of capture attempts were successful. Most successful prey captures involved reaching for, or leaping from, 90° or 60° supports in a horizontal or downward direction onto prey less than 0.6 m away. Virtually all prey captures were in arboreal locations, despite much higher densities of crickets on enclosure floors. Prey capture rates during the first hour of the nocturnal activity period were positively correlated with arboreal cricket densities. At constant arboreal cricket densities, capture rates were negatively correlated with ambient light intensity, with optimum levels for prey capture ranging from 0.1 to 2.0 Lux. In terms of social behavior, these T. bancanus were nongregarious. Females enforced interindividual spacing by chasing and displacing males. Chase/displacement rates increased significantly during late pregnancy and lactation, apparently in an attempt to keep males from harassing infants. There was no direct male parental care. Infants were precocial at birth, and grew at a rate of 0.35–0.5 g/day, until nutritional weaning at approximately 60 days of age. The implications of specialized predatory morphology and behavior for management are discussed. © 1993 Wiley-Liss, Inc.     

Diel and seasonal locomotor activity patterns in Arctic charr, Salvelinm alpinus (L.)

One-year-old Arctic charr, Sulvelinus alpinus (L.), of the Hornavan strain were tested from February 1985 to January 1986 in an attempt to get an increased understanding of the annual rheotactic behaviour as well as the die1 and seasonal locomotor activity pattern. An annular stream tank equipped with photocells was used to measure the direction of swimming movements as well as the number of passings. From February to late May the locomotor activity was low but increased in July and peaked in September. After November the locomotor activity was again at low winter levels. During the activity peak from July to November the majority ofall movements was directed against the current while no preference for direction was noted during the rest of the year. The high level of swimming movements directed against the current in late summer and autumn may be related to an innate habitat change. From February until June, the charr exhibited a bimodal diurnal activity pattern. In July activity was evenly spread over the whole 24- hour period and in August and September activity was again mainly diurnal with a bimodal pattern. In October and November the activity was mainly nocturnal and in December and January activity was concentrated in the short light period. Both annual and die1 activity are discussed in relation to earlier findings in general locomotor activity in Arctic charr and other salmonids.