scholarly journals Anti-Predator Vigilance as an Indicator of the Costs and Benefits of Supplemental Feeding in Newly Released ‘Alalā (Corvus hawaiiensis)

2021 ◽  
Vol 2 ◽  
Author(s):  
Heather N. Lee ◽  
Alison L. Greggor ◽  
Bryce Masuda ◽  
Ronald R. Swaisgood
Keyword(s):  
Predation Risk ◽  
Group Size ◽  
Conservation Strategy ◽  
Food Sources ◽  
Supplemental Feeding ◽  
Costs And Benefits ◽  
Additional Food ◽  
Dynamic Decisions ◽  
Feeder Design ◽  
Over Time

Although supplemental feeding is commonly used as a conservation strategy during animal translocations, it comes with a number of pros and cons which can be hard to quantify. Providing additional food resources may lead to improved physical health, survivorship, and reproduction. However, offering predictable food sources could make individuals more conspicuous to predators and less aware of their surroundings, disrupting their natural predator-prey dynamic. Decisions such as release cohort size and supplemental feeder design could influence the balance of these costs and benefits, depending on how animals behave in the face of predation risk and static food sources. Additionally, animals released to the wild from long term human care must balance foraging and predation risk while adjusting to a novel environment. To help conservation managers make informed decisions in light of these potential costs, we studied the behavior of a cohort of 11 conservation-bred ‘alalā (Corvus hawaiiensis) at supplemental feeding stations after release into the wild. Vigilance, foraging behavior and social group size was quantified via 1,320 trail camera videos of ‘alalā over the span of 12 months. We found that vigilance increased over time since release, suggesting that ‘alalā learn and adjust to their novel surroundings. Both vigilance and eating decreased with group size, indicating that although conspecifics may share the burden of scanning for threats, they also increase competition for food. We also found that the design of the feeder may have limited birds' abilities to express anti-predator behavior since less vigilance was observed in individuals that manipulated the feeder. Yet, birds may have been able to offset these costs since they increasingly scrounged for food scraps next to the feeder as time progressed. We discuss how changes to behavior over time, social interactions, and feeder design should all be considered when planning supplemental feeding as part of wildlife translocations.

Hunted hunters? Effect of group size on predation risk and growth in the Australian subsocial crab spider Diaea ergandros

2013 ◽  
Vol 67 (5) ◽  
pp. 785-794 ◽  
Author(s):  
Bianca Unglaub ◽  
Jasmin Ruch ◽  
Marie E. Herberstein ◽  
Jutta M. Schneider
Keyword(s):  
Predation Risk ◽  
Group Size ◽  
Crab Spider

scholarly journals Vertical Distribution of Arthropod Assemblages and the Effects of Weather Conditions on Arthropod Rain in a Temperate Conifer Forest

2021 ◽  
Vol 4 ◽  
Author(s):  
Tomohiro Yoshida ◽  
Yasunori Kusunoki ◽  
Yuya Fukano ◽  
Naoki Hijii
Keyword(s):  
Vertical Distribution ◽  
Weather Conditions ◽  
Vertical Stratification ◽  
Food Sources ◽  
Conifer Forest ◽  
Additional Food ◽  
Temperature And Precipitation ◽  
Taxonomic Groups ◽  
Forest Arthropods ◽  
Pan Traps

Vertical stratification of forests results in the occurrence of different arthropod assemblages between the vertical layers. Fallen arthropods from the canopy layers (i.e., “arthropod rain”) are additional food sources for predators thriving on the forest floor (FF). However, the abundances of arthropods are strongly affected by weather conditions and vertical stratification. Therefore, in this study, we investigated the vertical distribution of arthropod assemblages and effects of temperature and precipitation on the arthropod rain in a temperate conifer (Cryptomeria japonica) forest. Arthropods were collected by water-pan traps and trunk-sticky traps in the upper canopy (UC; 16 m), lower canopy (10 m), and FF (0.5 m). Among the fallen arthropods collected by water-pan traps, wandering detritivores, and herbivores were more abundant ranging from the FF to the UC, whereas the abundance of wandering predators (mainly spiders) was similar in the upper and lower canopies. However, detritivores, herbivores, and predators showed the highest abundance in the UC among the flying arthropods. Wandering arthropods moved upward from the FF toward the tree trunks more frequently than downward, indicating the importance of arthropod immigration from the ground to arboreal habitats. Temperature and precipitation had different effects on fallen and moving arthropods among different taxonomic groups. Flying arthropods were affected only by temperature, while wandering detritivores and herbivores were affected by precipitation and temperature. Thus, the abundance of wandering and flying arthropods differed among the vertical layers of a temperate conifer forest; additionally, arthropod rain was closely associated with weather conditions.

scholarly journals Group-size-mediated habitat selection and group fusion–fission dynamics of bison under predation risk

Ecology ◽  
2009 ◽  
Vol 90 (9) ◽  
pp. 2480-2490 ◽  
Author(s):  
Daniel Fortin ◽  
Marie-Eve Fortin ◽  
Hawthorne L. Beyer ◽  
Thierry Duchesne ◽  
Sabrina Courant ◽  
...  
Keyword(s):  
Habitat Selection ◽  
Predation Risk ◽  
Group Size ◽  
Group Fusion

Ecological drivers of group size in female Alpine chamois, Rupicapra rupicapra

Mammalia ◽  
2015 ◽  
Vol 79 (4) ◽  
Author(s):  
Roberta Chirichella ◽  
Andrea Mustoni ◽  
Marco Apollonio
Keyword(s):  
Predation Risk ◽  
Energy Intake ◽  
Group Size ◽  
Food Availability ◽  
Herd Size ◽  
Rupicapra Rupicapra ◽  
Trade Off ◽  
Mammalian Herbivores ◽  
Alpine Chamois

AbstractIn large mammalian herbivores, an increase in herd size not only reduces predation risk but also energy intake. As a consequence, the size of the groups made up by herbivores is often assumed to be the outcome of a trade-off depending on local predation risk and food availability. We studied Alpine chamois (

scholarly journals Prey synchronize their vigilant behaviour with other group members

2007 ◽  
Vol 274 (1615) ◽  
pp. 1287-1291 ◽  
Author(s):  
Olivier Pays ◽  
Pierre-Cyril Renaud ◽  
Patrice Loisel ◽  
Maud Petit ◽  
Jean-François Gerard ◽  
...  
Keyword(s):  
Predation Risk ◽  
Group Size ◽  
Prey Species ◽  
Group Members ◽  
The Individual ◽  
The Cost ◽  
Group Member

It is generally assumed that an individual of a prey species can benefit from an increase in the number of its group's members by reducing its own investment in vigilance. But what behaviour should group members adopt in relation to both the risk of being preyed upon and the individual investment in vigilance? Most models assume that individuals scan independently of one another. It is generally argued that it is more profitable for each group member owing to the cost that coordination of individual scans in non-overlapping bouts of vigilance would require. We studied the relationships between both individual and collective vigilance and group size in Defassa waterbuck, Kobus ellipsiprymnus defassa , in a population living under a predation risk. Our results confirmed that the proportion of time an individual spent in vigilance decreased with group size. However, the time during which at least one individual in the group scanned the environment (collective vigilance) increased. Analyses showed that individuals neither coordinated their scanning in an asynchronous way nor scanned independently of one another. On the contrary, scanning and non-scanning bouts were synchronized between group members, producing waves of collective vigilance. We claim that these waves are triggered by allelomimetic effects i.e. they are a phenomenon produced by an individual copying its neighbour's behaviour.

scholarly journals How long do anti-predator interventions remain effective? Patterns, thresholds and uncertainty

2019 ◽  
Vol 6 (9) ◽  
pp. 190826 ◽  
Author(s):  
Igor Khorozyan ◽  
Matthias Waltert
Keyword(s):  
Systematic Review ◽  
Temporal Trend ◽  
Supplemental Feeding ◽  
Temporal Dimension ◽  
Trend Line ◽  
Know How ◽  
Non Invasive ◽  
Effective Interventions ◽  
Mammalian Predators ◽  
Over Time

Human–predator conflicts are globally widespread, and effective interventions are essential to protect human assets from predator attacks. As effectiveness also has a temporal dimension, it is of importance to know how long interventions remain most effective and to determine time thresholds at which effectiveness begins to decrease. To address this, we conducted a systematic review of the temporal changes in the effectiveness of non-invasive interventions against terrestrial mammalian predators, defining a temporal trend line of effectiveness for each published case. We found only 26 cases from 14 publications, mainly referring to electric fences ( n = 7 cases) and deterrents ( n = 7 cases). We found electric fences and calving control to remain highly effective for the longest time, reducing damage by 100% for periods between three months and 3 years. The effectiveness of acoustical and light deterrents as well as guarding animals eroded quite fast after one to five months. Supplemental feeding was found to be counter-productive by increasing damage over time instead of reducing it. We stress that it is vital to make monitoring a routine requirement for all intervention applications and suggest to standardize periods of time over which monitoring can produce meaningful and affordable information.

Daily Rhythms of Female Self-maintenance Correlate with Predation Risk and Male Nest Attendance in a Biparental Wader

2020 ◽  
Vol 35 (5) ◽  
pp. 489-500 ◽  
Author(s):  
Kateřina Brynychová ◽  
Miroslav E. Šálek ◽  
Eva Vozabulová ◽  
Martin Sládeček
Keyword(s):  
Parental Care ◽  
Predation Risk ◽  
Video Recording ◽  
Nest Attendance ◽  
Daily Rhythms ◽  
Female Self ◽  
Fitness Consequences ◽  
Vanellus Vanellus ◽  
Lack Of Sleep ◽  
Over Time

Parents make tradeoffs between care for offspring and themselves. Such a tradeoff should be reduced in biparental species, when both parents provide parental care. However, in some biparental species, the contribution of one sex varies greatly over time or between pairs. How this variation in parental care influences self-maintenance rhythms is often unclear. In this study, we used continuous video recording to investigate the daily rhythms of sleep and feather preening in incubating females of the Northern Lapwing ( Vanellus vanellus), a wader with a highly variable male contribution to incubation. We found that the female’s sleep frequency peaked after sunrise and before sunset but was low in the middle of the day and especially during the night. In contrast, preening frequency followed a 24-h rhythm and peaked in the middle of the day. Taken together, incubating females rarely slept or preened during the night, when the predation pressure was highest. Moreover, the sleeping and preening rhythms were modulated by the male contribution to incubation. Females that were paired with more contributing males showed a stronger sleep rhythm but also a weaker preening rhythm. If more incubating males also invest more in nest guarding and deterring daylight predators, their females may afford more sleep on the nest during the day and preen more when they are off the nest. Whether the lack of sleep in females paired with less caregiving males has fitness consequences awaits future investigation.

Linking instream wood recruitment to adjacent forest development in landscapes driven by stand-replacing disturbances: a conceptual model to inform riparian and stream management

2020 ◽  
Vol 28 (4) ◽  
pp. 517-527
Author(s):  
Kyle D. Martens ◽  
Daniel C. Donato ◽  
Joshua S. Halofsky ◽  
Warren D. Devine ◽  
Teodora V. Minkova
Keyword(s):  
Conceptual Model ◽  
Pacific Northwest ◽  
Timber Harvest ◽  
Riparian Forests ◽  
Conservation Strategy ◽  
Forest Development ◽  
Stage Of Development ◽  
Instream Wood ◽  
Shaped Pattern ◽  
Over Time

Instream wood plays an important role in stream morphology and creation of fish habitat in conifer forests throughout the temperate zone. In some regions, such as the US Pacific Northwest, many streams currently have reduced amounts of instream wood due to past management activities (timber harvest, wood removal, etc.). These reductions exist against a backdrop of naturally dynamic amounts and distributions of instream wood, which likely fluctuate over time based in part on the stage of development (disturbance and succession) in adjacent riparian forests. Despite many studies on both forest development and instream wood accumulation, the linkages between these processes have not been fully described, particularly as they relate to stream restoration needs. In this paper, we combine literature on forest development, disturbance, and processes that drive instream wood recruitment to more explicitly connect the temporal dynamics of stream wood inputs with the dynamics of adjacent riparian forests. We use moist forests of the Pacific Northwest as an exemplary system, from which to draw broadly applicable patterns for landscapes influenced by stand-replacing disturbance regimes. This conceptual model highlights a U-shaped pattern of instream wood recruitment, in which instream wood is highest after a stand-replacing disturbance and during the old-growth stage, and lowest through the middle stages of forest development (currently the most abundant stages in many landscapes as a result of past forest management practices). This mid-successional period of scarce wood is likely exacerbated in streams with a history of wood removal. The U-shaped pattern suggests that, without higher-than-average levels of disturbance, many streams in landscapes dominated by mid-successional second-growth forests (∼30–80 yr old) will be deficient of instream wood until forest stands are over 200 years old. As such, the balance between the predominant riparian conservation strategy of passive restoration (e.g., unharvested riparian reserves) and the alternative of active restoration (e.g., wood additions and (or) riparian stand treatments) should be carefully considered, depending on management objectives, site context, and potential tradeoffs over time.

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