Effects of levels of human exposure on flight initiation distance and distance to refuge in foraging eastern gray squirrels (Sciurus carolinensis)

2011 ◽  
Vol 89 (9) ◽  
pp. 823-830 ◽  
Author(s):  
S.C. Engelhardt ◽  
R.B. Weladji
Keyword(s):  
Human Exposure ◽  
Sciurus Carolinensis ◽  
Flight Initiation Distance ◽  
Trade Offs ◽  
Decision Making Processes ◽  
Prey Escape ◽  
Exposure Levels ◽  
Escape Decision ◽  
Flight Initiation ◽  
Eastern Gray Squirrels

Flight initiation distance (FID), the distance at which an organism begins to flee from an approaching predator or threat, is associated to prey escape decision-making processes with benefit and cost trade-offs to remaining in a patch. Factors that may affect FID can be altered by human-stimulated predation risk, although the magnitude of response may depend on human exposure. We investigated how FID and distance to refuge of foraging eastern gray squirrels ( Sciurus carolinensis Gmelin, 1788), vary in seven sites corresponding to three levels of human exposure. We predicted that both FID and distance to refuge increase as exposure to human stimuli decreases; FID increases with the starting distance of the approaching human; and FID increases with distance to refuge. We found that FID increased with decreasing human exposure and that FID increased with increasing starting distance. We found no difference in distance to refuge between exposure levels. Our results suggest that risk posed to gray squirrels in areas frequently visited by humans is minimized or reduced, leading to differences in FID between exposure levels and may be attributed to habituation to increased nonlethal stimuli in the form of exposure to humans.

Opposite companion effect on flight initiation distance in sympatric species: plateau pika (Ochotona curzoniae) and White-rumped Snowfinch (Onychostruthus taczanowskii)

2016 ◽  
Vol 94 (2) ◽  
pp. 109-114 ◽  
Author(s):  
He Zhang ◽  
Wenjing Li ◽  
Yanping Hu ◽  
Yanming Zhang
Keyword(s):  
Linear Models ◽  
Antipredator Behavior ◽  
Sympatric Species ◽  
Flight Initiation Distance ◽  
Plateau Pika ◽  
Escape Theory ◽  
Ochotona Curzoniae ◽  
Positive Correlations ◽  
Escape Decision ◽  
Flight Initiation

There are many factors influencing prey’s risk perception and escape decision during predator–prey encounters. The distance at which animals move away from perceived danger (often quantified as flight initiation distance or FID) has been used by behavioral ecologists to understand the economics of antipredator behavior. Using general linear models, we investigated escape decision-making processes in plateau pika (Ochotona curzoniae (Hodgson, 1858)) and White-rumped Snowfinch (Onychostruthus taczanowskii (Prjevalsky, 1876), formerly known as Montifringilla taczanowskii Przewalski, 1876) together and we found that (i) there are significant positive correlations between starting distance and FID in both species; (ii) pika escapes at a longer distance from an approaching intruder when it is far from its burrow; (iii) foraging animals tolerate closer distances than watching ones, both in pikas and in Snowfinches; (iv) conspecifics seem to have no effect on pikas’ escaping behavior, while the appearance of Snowfinches dramatically decreases the FID of pikas. On the contrary, conspecifics significantly decrease the FID of Snowfinches, while the presence of pikas has no effects. These findings provide new evidence, which are consistent with optimal escape theory. These novel results in multispecies interactions prompt us to pay attention to the potential relationship between pikas and Snowfinches, as well as the “bird–pika in one hole” phenomenon.

Behaviourally mediated biases in transect surveys: a predation risk sensitivity approach

2020 ◽  
Vol 98 (11) ◽  
pp. 697-704
Author(s):  
Lawrence M. Dill ◽  
Alejandro Frid
Keyword(s):  
General Framework ◽  
Behavioural Ecology ◽  
Risk Sensitivity ◽  
Flight Initiation Distance ◽  
Approach And Avoidance ◽  
Trade Offs ◽  
Transect Counts ◽  
Sensitivity Approach ◽  
Extensive Body ◽  
Flight Initiation

Variation in the behaviour of individuals or species, particularly their propensity to avoid or approach human observers, their conveyances (e.g., cars), or their proxy devices (e.g., drones) has been recognized as a source of bias in transect counts. However, there has been little attempt to predict the likelihood or magnitude of such biases. Behavioural ecology provides a rich source of theory to develop a general framework for doing so. For example, if animals perceive observers as predators, then the extensive body of research on responses of prey to their predators may be applied to this issue. Here we survey the literature on flight initiation distance (the distance from a predator or disturbance stimulus at which prey flee) for a variety of taxa to suggest which characteristics of the animal, the observer, and the environment may create negatively biased counts. We also consider factors that might cause prey to approach observers, creating positive bias, and discuss when and why motivation for both approach and avoidance might occur simultaneously and how animals may resolve such trade-offs. Finally, we discuss the potential for predicting the extent of the behaviourally mediated biases that may be expected in transect counts and consider ways of dealing with them.

Sex and refuge distance influence escape decision in a Liolaemus lizard when it is approached by a terrestrial predator

Behaviour ◽  
2019 ◽  
Vol 156 (9) ◽  
pp. 909-925 ◽  
Author(s):  
Carla A. Salido ◽  
Natalin S. Vicente
Keyword(s):  
Decision Making ◽  
High Speed ◽  
Sexual Dichromatism ◽  
Flight Initiation Distance ◽  
Sex Influence ◽  
Terrestrial Predator ◽  
Microclimatic Conditions ◽  
Escape Decision ◽  
Escape Speed ◽  
Flight Initiation

Abstract The decision of when and how to escape result crucial for animals because it can result in an interruption to contribute to their fitness. In the present study, we analysed whether speed attack, sex and type of refuge influenced the flight initiation distance (FID) and the closest refuge distance (CRD) in Liolaemus pacha lizards. We also compared the use of different type of refuges. Sex influence both CRD and FID, which would be discussed according to the size of their home range, the escape speed and sexual dichromatism. The interaction between speed and type of refuge used, influence CRD, suggesting that lizards perceived different predation risks. At high-speed approaches, lizards chose the closest refuge, rocks; while at low-speed approaches, lizards chose shrubs as a refuge, mainly the small ones. Lizard’s decision-making is discussed in relation to the refuge protection, their microclimatic conditions and visibility.

The influence of distance to refuge on flight initiation distance in the gray squirrel (Sciurus carolinensis)

1989 ◽  
Vol 67 (1) ◽  
pp. 233-235 ◽  
Author(s):  
Lawrence M. Dill ◽  
Robert Houtman
Keyword(s):  
Sciurus Carolinensis ◽  
Flight Initiation Distance ◽  
Gray Squirrel ◽  
Tree Squirrels ◽  
Flight Initiation ◽  
Model Predator

Gray squirrels (Sciurus carolinensis) typically run to the nearest tree to escape from predators they encounter while foraging on the ground. As the risk of capture increases with distance from the refuge tree, squirrels feeding far from trees should have greater flight initiation distances than those feeding closer by. This prediction was confirmed: flight initiation distance in response to a motorized model predator (a cat) increased as distance to refuge increased. This could not be attributed to any effect of distance to refuge on vigilance.

scholarly journals European birds adjust their flight initiation distance to road speed limits

2013 ◽  
Vol 9 (5) ◽  
pp. 20130417 ◽  
Author(s):  
Pierre Legagneux ◽  
Simon Ducatez
Keyword(s):  
Habitat Structure ◽  
Territory Size ◽  
Speed Limit ◽  
Vehicle Speed ◽  
Flight Initiation Distance ◽  
Speed Limits ◽  
Behavioural Responses ◽  
Road Speed ◽  
Flight Initiation ◽  
Local Speed

Behavioural responses can help species persist in habitats modified by humans. Roads and traffic greatly affect animals' mortality not only through habitat structure modifications but also through direct mortality owing to collisions. Although species are known to differ in their sensitivity to the risk of collision, whether individuals can change their behaviour in response to this is still unknown. Here, we tested whether common European birds changed their flight initiation distances (FIDs) in response to vehicles according to road speed limit (a known factor affecting killing rates on roads) and vehicle speed. We found that FID increased with speed limit, although vehicle speed had no effect. This suggests that birds adjust their flight distance to speed limit, which may reduce collision risks and decrease mortality maximizing the time allocated to foraging behaviours. Mobility and territory size are likely to affect an individuals' ability to respond adaptively to local speed limits.

scholarly journals Increasing corvid tolerance to humans in urban ecosystems with increasing latitude

2020 ◽  
Vol 64 (4) ◽  
Author(s):  
Nadezhda Poddubnaya ◽  
Tatyana Korotkova ◽  
Polina Vanicheva
Keyword(s):  
Environmental Factors ◽  
Human Disturbance ◽  
Urban Ecosystems ◽  
Flight Initiation Distance ◽  
Protection Measures ◽  
Non Invasive ◽  
Alert Distance ◽  
Behaviour Changes ◽  
Hooded Crows ◽  
Flight Initiation

The rapid growth of cities causes behaviour changes in birds in response to urban environmental factors. The avian response to human disturbance has recently been studied by a non-invasive research tool as an alert distance (AD) and a flight initiation distance (FID) assessment. The tolerance of hooded crows (n = 395), jackdaws (n = 394) and rooks (n = 169) to humans was assessed by AD and FID. It was shown that the FID of all species is maximal during the summer, when the parents send clear “danger—fly away” signals to the young and the birds fly away. The AD and FID of the three species reliably correlates with the season. Rooks showed FID species-specificity in seven cities of Eastern Europe. Comparison of the attitude of birds to people in cities that have similarities in human culture showed that tolerance increases with increasing latitude in all species and is statistically significant only in the jackdaw. This should be taken into account in environmental protection measures.

scholarly journals Advancing Relevance, Credibility, Legitimacy, and Effectiveness as a Heuristic for Local-Parallel Scenarios

2021 ◽  
Vol 3 ◽  
Author(s):  
Nicholas A. Cradock-Henry ◽  
Bob Frame
Keyword(s):  
Decision Making ◽  
Local Level ◽  
Global Scale ◽  
Global Changes ◽  
Scenario Development ◽  
Personal Time ◽  
Trade Offs ◽  
Economic Trends ◽  
Decision Making Processes ◽  
Competing Priorities

The parallel scenario process provides a framework for developing plausible scenarios of future conditions. Combining greenhouse gas emissions, social and economic trends, and policy responses, it enables researchers and policy makers to consider global-scale interactions, impacts and implications of climate change. Increasingly, researchers are developing extended scenarios, based on this framework, and incorporating them into adaptation planning and decision-making processes at the local level. To enable the identification of possible impacts and assess vulnerability, these local-parallel scenarios must successfully accommodate diverse knowledge systems, multiple values, and competing priorities including both “top down” modeling and “bottom-up” participatory processes. They must link across scales, to account for the ways in which global changes affect and influence decision-making in local places. Due to the growing use of scenarios, there is value in assessing these developments using criteria or, more specifically, heuristics that may be implicitly acknowledged rather than formally monitored and evaluated. In this Perspective, we reflect on various contributions regarding the value of heuristics and propose the adoption of current definitions for Relevance, Credibility, and Legitimacy for guiding local scenario development as the most useful as well as using Effectiveness for evaluation purposes. We summarize the internal trade-offs (personal time, clarity-complexity, speed-quality, push-pull) and the external stressors (equity and the role of science in society) that influence the extent to which heuristics are used as “rules of thumb,” rather than formal assessment. These heuristics may help refine the process of extending the parallel scenario framework to the local and enable cross-case comparisons.

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