Effect of visibility on time allocation and escape decisions in crimson rosellas

2006 ◽  
Vol 54 (5) ◽  
pp. 363 ◽  
Author(s):  
Jennifer S. Boyer ◽  
Laura L. Hass ◽  
Matthew H. Lurie ◽  
Daniel T. Blumstein
Keyword(s):  
Time Allocation ◽  
Habitat Structure ◽  
Antipredator Behaviour ◽  
Flight Initiation Distance ◽  
Perception Of Risk ◽  
White Sheet ◽  
Two Stages ◽  
Flight Initiation

Most studies of antipredator behaviour have focused on a single behaviour at a time, but ubiquitous factors may simultaneously influence a variety of activities. Habitat structure influences visibility, which influences both the ability of prey to detect and respond to their predators. We studied how habitat visibility influenced time allocation and escape decisions of crimson rosellas (Playcercus elegans). We examined the effect of visibility on time allocated to looking, locomotion and foraging. We measured escape decisions by experimentally approaching rosellas until they fled. We measured visibility by standing 12 m away from a 1-m2 white sheet containing 36 points and counting the number of points that were visible. As measured, visibility influenced time allocated to both foraging and locomotion. However, there was no effect of visibility on flight-initiation distance or two other related measures of escape (a measure of the latency to detect an approaching threat or the latency to flee once the threat was detected). Therefore, crimson rosellas modified their behaviour as a function of visibility, but this did not influence their decision to flee from an approaching human. We infer that they are sensitive to variation in visibility, but that this does not influence their overall perception of risk as we measured it. These two stages of antipredator behaviour may thus be largely independent; ubiquitous factors need not have ubiquitous effects on different aspects of antipredator behaviour.

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 Do infections with parasites and exposure to pollution affect susceptibility to predation in johnny darters (Etheostoma nigrum)?

2010 ◽  
Vol 88 (12) ◽  
pp. 1218-1225 ◽  
Author(s):  
Rachel J. Krause ◽  
James W.A. Grant ◽  
J. Daniel McLaughlin ◽  
David J. Marcogliese
Keyword(s):  
Antipredator Behaviour ◽  
Benthic Fish ◽  
Flight Initiation Distance ◽  
Capture Time ◽  
Parasite Infections ◽  
Natural Predation ◽  
The Brain ◽  
Flight Initiation ◽  
St Lawrence River

Johnny darters ( Etheostoma nigrum Rafinesque, 1820) were collected from five localities in the St. Lawrence River in southwestern Quebec to test the effects of natural parasite infections and exposure in situ to pollution on their antipredator behaviour. Three measures of antipredator behaviour were made: (1) capture time (i.e., the time taken to catch individual fish) was used as a proxy for the ability to evade predation, (2) capture order was the order in which fish kept in a single tank were taken from the tank, and (3) flight initiation distance was the distance at which the fish moved when approached by a model predator. Only capture time showed a significant correlation with parasitism or pollution status. A nonparametric permutational multivariate ANOVA showed that capture time was significantly correlated with capture location and the abundance of the brain-encysting trematode Ornithodiplostomum Dubois, 1936. Infection with Ornithodiplostomum sp. may have led to an increase in activity, which would be maladaptive for this cryptic, benthic fish under natural predation conditions. Pollution may have an indirect effect on predator susceptibility in johnny darters, by reducing the abundance of a behaviour-modifying parasite.

scholarly journals Fear in animals: a meta-analysis and review of risk assessment

2005 ◽  
Vol 272 (1581) ◽  
pp. 2627-2634 ◽  
Author(s):  
Theodore Stankowich ◽  
Daniel T Blumstein
Keyword(s):  
Meta Analysis ◽  
Effect Sizes ◽  
Relative Importance ◽  
Flight Initiation Distance ◽  
Extensive Review ◽  
Motivational State ◽  
Perception Of Risk ◽  
Factors Influencing ◽  
Predator Behaviour ◽  
Flight Initiation

The amount of risk animals perceive in a given circumstance (i.e. their degree of ‘fear’) is a difficult motivational state to study. While many studies have used flight initiation distance as a proxy for fearfulness and examined the factors influencing the decision to flee, there is no general understanding of the relative importance of these factors. By identifying factors with large effect sizes, we can determine whether anti-predator strategies reduce fear, and we gain a unique perspective on the coevolution of predator and anti-predator behaviour. Based on an extensive review and formal meta-analysis, we found that predator traits that were associated with greater risk (speed, size, directness of approach), increased prey distance to refuge and experience with predators consistently amplified the perception of risk (in terms of flight initiation distance). While fish tolerated closer approach when in larger schools, other taxa had greater flight initiation distances when in larger groups. The presence of armoured and cryptic morphologies decreased perception of risk, but body temperature in lizards had no robust effect on flight initiation distance. We find that selection generally acts on prey to be sensitive to predator behaviour, as well as on prey to modify their behaviour and morphology.

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.

Take only pictures, leave only… Cameras influence marmot vigilance but not perceptions of risk

2021 ◽  
Author(s):  
Kenta Uchida ◽  
Albert A. Burkle ◽  
Daniel T. Blumstein
Keyword(s):  
Risk Assessment ◽  
Predation Risk ◽  
Visual Stimulus ◽  
Zoom Lens ◽  
Flight Initiation Distance ◽  
Vulnerable Species ◽  
Species Ranges ◽  
Perceptions Of Risk ◽  
Flight Initiation ◽  
Subsequent Risk

Ecotourism promotes conservation efforts while also allowing for low impact observation of wildlife. Many ecotourists photograph wildlife and photography plays an important role in focusing the public’s attention on nature. Although photography is commonly believed to be a low impact activity, how the visual stimulus of a camera influences wildlife remains unknown. Since animals are known to fear eyes pointed towards them, we predicted that a camera with a large zoom lens would increase animal’s vigilance levels. Using yellow-bellied marmots (Marmota flaviventer) as a mammalian model, and adopting a behavioural approach to identify how marmots responded to cameras, we experimentally quantified vigilance and flight initiation distance towards humans when marmots were approached with and without a camera. While a camera was pointed at an individual, marmots allocated less time to searching predators and increased time to looking at the observer than they did without a camera. However, whether a camera was pointed at a marmot or not had no effect on the distance the marmot flushed. Our results indicated that cameras distracted marmots but did not influence subsequent risk assessment (i.e., flight initiation distance); marmots may be curious about cameras but were not threatened by them. Capturing animals’ attentions reduces searching for predators and may increase the vulnerability to predation. Therefore, regulating photography in locations where predation risk is high or vulnerable species ranges’ overlap with humans may be required to reduce photography’s impact on wildlife.

Crypsis influences escape decisions in the Round-tailed Horned Lizard (Phrynosoma modestum)

2010 ◽  
Vol 88 (10) ◽  
pp. 1003-1010 ◽  
Author(s):  
William E. Cooper, ◽  
Wade C. Sherbrooke
Keyword(s):  
Body Temperature ◽  
Predation Risk ◽  
Upright Posture ◽  
Flight Initiation Distance ◽  
Lower Body ◽  
Running Speed ◽  
Predator Prey ◽  
Sandy Area ◽  
Lower Body Temperature ◽  
Flight Initiation

Flight initiation distance (predator–prey distance when escape begins) increases as predation risk increases. Prey should have longer flight initiation distance when their background, movement, or current posture reduces crypsis. Flight initiation distance of ectotherms may increase at lower body temperature to compensate for slower running speed. However, for cryptic prey, fleeing might increase the probability of being detected. The Round-tailed Horned Lizard ( Phrynosoma modestum Girard, 1852) is eucryptic and resembles small stones. We predicted that flight initiation distance by P. modestum is shorter among stones than on uniform sand. Because movement and upright posture disrupt crypsis, we predicted that flight initiation distance is greater after movement and when standing than when still and lying on the ground. As predicted, flight initiation distances were shorter on a rocky than sandy area, when lying flat than standing, and while immobile than after moving. We measured running speed and flight initiation distance to determine relationships among body temperature, speed, and escape decisions. Running speed and flight initiation distance were reduced at lower body temperature, suggesting that crypsis reinforced by immobility is more advantageous than longer flight initiation distance for cool, slow lizards. The lizards adjusted escape decisions to current effectiveness of crypsis and escape ability.

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