Habitat choice and vigilance behaviour of brush-tailed rock-wallabies (Petrogale penicillata) within their nocturnal foraging ranges

2003 ◽  
Vol 30 (4) ◽  
pp. 355 ◽  
Author(s):  
Kerryn Carter ◽  
Anne W. Goldizen
Keyword(s):  
Light Intensity ◽  
Predation Risk ◽  
Habitat Choice ◽  
Night Vision ◽  
Energy Requirements ◽  
Vigilance Behaviour ◽  
Nocturnal Foraging ◽  
Limited Food ◽  
High Winds ◽  
Foraging Ranges

Habitat choice by brush-tailed rock-wallabies (Petrogale penicillata) in south-east Queensland was investigated by comparing the attributes of the nocturnal foraging locations that they selected with those of random locations within a radius of 50 m. Brush-tailed rock-wallabies were shown to select foraging locations on the basis of forage quality and/or their ability to see predators, rather than protection from predators amongst vegetation that could conceal them. Habitat choice may have been affected by limited food availability, as this study was conducted in the winter dry season. The attributes of foraging locations that brush-tailed rock-wallabies perceived as increasing their predation risk were assessed by recording the proportion of time that brush-tailed rock-wallabies spent vigilant while foraging. To measure vigilance, focal animals were observed with a night-vision scope for two minutes and the proportions of time spent vigilant and feeding were recorded. No measured feature of foraging locations was related to higher vigilance levels, suggesting that brush-tailed rock-wallabies did not alter their vigilance whether sheltered amongst grass tussocks or in open habitat, or whether feeding on good quality or poorer quality vegetation. Vigilance levels significantly declined as overnight temperatures decreased, which may have resulted from higher energy requirements of brush-tailed rock-wallabies during winter. The only factors that were found to significantly increase vigilance levels were high winds and moonlit nights. On bright nights, brush-tailed rock-wallabies were very unsettled and during high winds they often did not emerge to feed. More information is needed about how macropods detect predators at night before the effects of wind and light intensity upon vigilance can be fully understood.

Interlake variation in growth and size structure of bluegill (Lepomis macrochirus): inverse analysis of an individual-based model

1998 ◽  
Vol 55 (2) ◽  
pp. 387-396 ◽  
Author(s):  
Nathan P Nibbelink ◽  
Stephen R Carpenter
Keyword(s):  
Predation Risk ◽  
Food Availability ◽  
Inverse Modeling ◽  
Habitat Structure ◽  
Size Structure ◽  
Lepomis Macrochirus ◽  
Habitat Choice ◽  
Selective Predation ◽  
Free Parameters ◽  
Contrasting Habitats

Habitat structure alters food availability and predation risk, thereby directly affecting growth, mortality, and size structure of fish populations. Size structure has often been used to infer patterns of resource abundance and predation. However, food availability and predation risk in contrasting habitats have proven difficult to measure in the field. We use an inverse modeling approach to estimate food availability and habitat choice parameters from changes in length distributions of bluegill (Lepomis macrochirus). The model suggests that dynamics of bluegill length distributions primarily reflect food availability and habitat choice. Bluegill behavior minimized effects of size-selective predation on size structure. Parameters for food availability and habitat choice were correlated. It was therefore not possible to attain unique estimates of food availability and habitat selection when both were free parameters. However, when one parameter was estimated independently, the other could be identified. In five Wisconsin lakes, seining studies were used to estimate the size at which bluegill switched from littoral to pelagic habitats. Using this measure of switch size in the model, we estimated food availability for bluegill in each lake. These estimates were positively correlated with observed growth (r2 = 0.91), demonstrating the model's ability to estimate food availability.

Anti-predator behaviour of kudu and impala in response to mimicked African wild dog presence: do age and sex matter?

Behaviour ◽  
2015 ◽  
Vol 152 (9) ◽  
pp. 1209-1228 ◽  
Author(s):  
Esther van der Meer ◽  
Hervé Fritz ◽  
Olivier Pays
Keyword(s):  
Predation Risk ◽  
Lycaon Pictus ◽  
High Quality ◽  
Vigilance Behaviour ◽  
African Wild Dog ◽  
African Wild Dogs ◽  
Tragelaphus Strepsiceros ◽  
Wild Dog ◽  
Wild Dogs ◽  
Aepyceros Melampus

Predators not only prey upon certain prey species, but also on certain age–sex classes within species. Predation risk and an individual’s response to this risk might therefore vary with an individual’s characteristics. We examined the proportion of time different age–sex classes of kudu (Tragelaphus strepsiceros) and impala (Aepyceros melampus) spent high quality vigilant (costly vigilance that detracts from all other activities) in response to mimicked predation risk by African wild dogs (Lycaon pictus). For both species predation risk was the main factor determining the investment in high quality vigilance behaviour. Age–sex class-specific responses were not related to age–sex class specific lethality risk presented by African wild dogs. For impala, regardless of predation risk, age seemed to have some effect on the investment in high quality vigilance with sub-adult impala spending more time high quality vigilant than adult impala, which is possibly why African wild dogs predominantly preyed upon adult impala.

scholarly journals The SYSTEM IDENTIFICATION OF FRIEND AND ENEMY USING NIGHT VISION CAMERA ON BATTLE ROBOT (CQB) USING PATTERN RECOGNITION METHOD

2021 ◽  
Vol 2 (Oktober) ◽  
pp. 15-23
Author(s):  
Eko Wahyu Pratama ◽  
Mohammad Ansori ◽  
Kusno Suryadi
Keyword(s):  
Pattern Recognition ◽  
System Identification ◽  
Light Intensity ◽  
Night Vision ◽  
Main Task ◽  
Pattern Recognition Method ◽  
Recognition Method ◽  
Accuracy Rate ◽  
Identification Process ◽  
Urban Warfare

Abstract – Indonesian Army has the main task of protecting against enemy attacks, which include forest battles as well as urban battles. The obstacle faced today is that in the process of urban warfare operations, infiltration and hostage rescue in buildings are still less efficient and optimal. The robot is designed with a system that can identify friends and foes using a Night Vision camera and the Pattern Recognition method. Pattern recognition is a symbolic grouping automatically that is done by a computer to find out objects or patterns. The results of the Night vision camera test are able to detect human objects with a maximum distance of 6 meters. This night vision scope has a fairly large accuracy rate of 83%. And light intensity has an influence on the identification process because if the light intensity is more than 200 lux then the system is not able to identify the object.

Do long-tailed macaques avoid large heterospecific carcasses?

Behaviour ◽  
2021 ◽  
pp. 1-12
Author(s):  
Jeffrey V. Peterson ◽  
Agustín Fuentes
Keyword(s):  
Predation Risk ◽  
Nonhuman Primate ◽  
Perceived Risk ◽  
Macaca Fascicularis ◽  
Future Research ◽  
Tree Line ◽  
Risk Of Predation ◽  
Vigilance Behaviour ◽  
Pathogen Avoidance

Abstract This anecdotal observation details the response of long-tailed macaques (Macaca fascicularis) to a heterospecific carcass. The subgroup of macaques we were following abruptly changed their direction of travel upon reaching a tree line while displaying silent vigilance behaviour. We later discovered a dog carcass in the area and concluded their behaviour may have been in response to the smell of that carcass. The carcass was not visible from the response point at the tree line due to its distance from that point (approximately 30 meters) and the uneven and densely vegetated terrain between. The macaques were therefore most likely responding to scent cues from the carcass. We suggest the observed vigilance behaviour is excessive under a strictly pathogen-avoidance explanation and may be understood as a response to a cue of potential predation risk. We review alternative explanations and suggest future research on nonhuman primate heterospecific carcass avoidance is necessary to fully assess the potential relation to perceived risk of predation.

scholarly journals Does Moonlight Increase Predation Risk for Elusive Mammals in Costa Rica?

2020 ◽  
Vol 13 ◽  
pp. 194008292095240
Author(s):  
Ryan T. Botts ◽  
Amy A. Eppert ◽  
Timothy J. Wiegman ◽  
Steven R. Blankenship ◽  
Abner Rodriguez ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Costa Rica ◽  
Predation Risk ◽  
Activity Patterns ◽  
Night Vision ◽  
Lunar Phase ◽  
Nocturnal Activity ◽  
Related Activity ◽  
Risk Of Predation ◽  
Increased Risk

An increasing body of evidence indicates that moonlight influences the nocturnal activity patterns of tropical mammals, both predators and prey. One explanation is that brighter moonlight is associated with increased risk of predation (Predation Risk hypothesis), but it has also been proposed that nocturnal activity may be influenced by the sensory ecology of a species, with species that rely on visual detection of food and danger predicted to increase their activity during bright moonlight, while species relying on non-visual senses should decrease activity (Visual Acuity hypothesis). Lack of an objective measure of “visual acuity” has made this second hypothesis difficult to test, therefore we employed a novel approach to better understand the role of lunar illumination in driving activity patterns by using the tapetum lucidum as a proxy for “night vision” acuity. To test the alternative predictions, we analyzed a large dataset from our long-term camera trap study in Costa Rica using activity overlap, relative abundance, and circular statistical techniques. Mixed models explored the influence of illumination factors (moonrise/set, cloud cover, season) and night vision acuity (tapetum type) on nocturnal and lunar phase-related activity patterns. Our results support the underlying assumptions of the predation risk and visual acuity models, but indicate that neither can fully predict lunar-related activity patterns. With diurnal human “super predators” forcing a global increase in activity during the night by mammals, our findings can contribute to a better understanding of nocturnal activity patterns and the development of conservation approaches to mitigate forced temporal niche shifts.

Nocturnal and diurnal foraging behaviour of brown bears (Ursus arctos) on a salmon stream in coastal British Columbia

2002 ◽  
Vol 80 (8) ◽  
pp. 1317-1322 ◽  
Author(s):  
D R Klinka ◽  
T E Reimchen
Keyword(s):  
British Columbia ◽  
Ursus Arctos ◽  
Night Vision ◽  
Black Bears ◽  
Spawning Migration ◽  
Brown Bears ◽  
Light Levels ◽  
Nocturnal Foraging ◽  
Consumption Rates ◽  
Coastal British Columbia

Brown bears (Ursus arctos) have been reported to be primarily diurnal throughout their range in North America. Recent studies of black bears during salmon migration indicate high levels of nocturnal foraging with high capture efficiencies during darkness. We investigated the extent of nocturnal foraging by brown bears during a salmon spawning migration at Knight Inlet in coastal British Columbia, using night-vision goggles. Adult brown bears were observed foraging equally during daylight and darkness, while adult females with cubs, as well as subadults, were most prevalent during daylight and twilight but uncommon during darkness. We observed a marginal trend of increased capture efficiency with reduced light levels (day, 20%; night, 36%) that was probably due to the reduced evasive behaviour of the salmon. Capture rates averaged 3.9 fish/h and differed among photic regimes (daylight, 2.1 fish/h; twilight, 4.3 fish/h; darkness, 8.3 fish/h). These results indicate that brown bears are highly successful during nocturnal foraging and exploit this period during spawning migration to maximize their consumption rates of an ephemeral resource.

scholarly journals Extrinsic and intrinsic factors influencing the emergence and return of Asian particolored bats Vespertilio sinensis

2021 ◽  
Author(s):  
Lei Feng ◽  
Hexuan Qin ◽  
Jingjing Li ◽  
Xin Li ◽  
Jiang Feng ◽  
...  
Keyword(s):  
Light Intensity ◽  
Predation Risk ◽  
Environmental Changes ◽  
Return Time ◽  
Reproductive Status ◽  
Lactation Period ◽  
Emergence Time ◽  
Extrinsic Factors ◽  
Activity Rhythms ◽  
Return Times

The circadian rhythm is an adaptive biological process, allows organisms to anticipate daily environmental changes and implement appropriate strategies. Circadian rhythms play a crucial role in the health and survival of organisms. However, little is known concerning how intrinsic and extrinsic factors affect animal daily rhythms in the field, especially in nocturnal animals. Here, we investigated the emergence and return times of Vesperilio sinensis, and also integrated environmental conditions (temperature, humidity and light intensity) and biotic factors (reproductive status and predation risk) to determine causes of variation in the activity rhythms of the bats. We found that variation in the first emergence time, the mid-emergence time, and the final return time were distinct. The results demonstrated that the emergence and return times of bats were affected by light intensity, reproductive status, and predation risk in a relatively complex pattern. Light intensity had the greatest contribution to activity rhythms. Moreover, we first investigated the effects of actual predators on the activity rhythms of bats; the results showed that the mid-emergence time of bats was earlier as predators were hunting, but the final return time was later when predators were present. This challenges the traditional view that high predation risk leads to later emergence and earlier return. Finally, our results also highlighted the importance of higher energy demands during the lactation period in bats to variation in activity rhythms. These results improve our understanding of the patterns and causes of variation in activity rhythms in bats and other nocturnal animals.

Rhythmic Behaviour of the Intertidal Amphipod Bathyporeia Pelagica

1970 ◽  
Vol 50 (4) ◽  
pp. 1057-1068 ◽  
Author(s):  
A. A. Fincham
Keyword(s):  
Light Intensity ◽  
Rocky Shore ◽  
Activity Rhythm ◽  
Foraging Activity ◽  
Corophium Volutator ◽  
Inhibiting Effect ◽  
Talitrus Saltator ◽  
Nocturnal Foraging ◽  
Controlled Illumination ◽  
Effect Of Light

Several authors have studied the rhythmic behaviour of amphipods, including Papi (1955) who demonstrated an endogenous solar time sense in Talitrus saltator which was used for navigation. Talitrids were also investigated by Featherston & Maclntyre (1957) who suggested that changes in light intensity triggered the nocturnal foraging activity. Enright (1961, 1962, 1963) tested the effects of pressure, temperature, light intensity, absence of sand and shaking on rhythmic behaviour of the intertidal and in-faunal amphipod Synchelidium. The activity rhythm of Corophium volutator has been reported by Morgan (1965) in which a peak occurred on the early ebb. Various rocky shore Peracarida including species of Gammarus also perform vertical migrations into the surf at night (Jansson & Källander, 1968); the inhibiting effect of light was proven by experiments with controlled illumination.

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