RSOS Response time of an avian prey to a simulated hawk attack is slower in darker conditions, but is independent of hawk colour morph
Carina Nebel
Petra Sumasgutner
Adrien Pajot
Arjun Amar
10.25375/uct.8332436.v2
https://zivahub.uct.ac.za/articles/dataset/RSOS_reaction_time_pigeon_pulley_experiment/8332436
<p>Manuscript published in the Royal Society Open Science:<br></p><p>Nebel, C., Sumasgutner, P., Pajot, A. and Amar A. Response times of an avian prey to a simulated hawk attack is slower in darker conditions, but is independent of hawk colour morph</p><p><br></p><p>Abstract:</p><p>To avoid
predation, many species rely on vision to detect predators and initiate an
escape response. The ability to detect predators may be lower in darker light
conditions or with darker backgrounds. For birds, however, this has never been
experimentally tested. We test the hypothesis that the response time of avian prey
(feral pigeon <i>Columbia livia f. domestica</i>)
to a simulated hawk attack (taxidermy mounted colour-polymorphic black
sparrowhawk <i>Accipiter melanoleucus</i>)
will differ depending on light levels or background colour. We predict that response
will be slower under darker conditions, which would translate into higher
predation risk. The speed of response of prey in relation to light level or
background colour may also interact with the colour of the predator, and this
idea underpins a key hypothesis proposed for the maintenance of different colour
morphs in polymorphic raptors. We therefore test whether speed of reaction is
influenced by the morph of the hawk (dark/light) in combination with light
conditions (dull/bright), or background colours (black/white). We predict slowest
responses to morphs under conditions that less contrast with the plumage of the
hawk (e.g. light morph under bright light or white background). In support of
our first hypothesis, pigeons reacted slower under duller light and with a black
background. However, we found no support for the second hypothesis, with response
times observed between the hawk morphs being irrespective of light levels or
background colour. Our findings experimentally confirm that birds detect avian predators
less efficiently under darker conditions. These conditions, for example, might
occur during early mornings or in dense forests, which could lead to changes in
anti-predator behaviours. However, our results provide no support that
different morphs may be maintained in a population due to differential
selective advantages linked to improved hunting efficiencies in different
conditions due to crypsis.</p>
2019-07-30 12:41:17
Predation Risk
Predator-Prey Interactions
experiment
colour polymorphism
bird of prey
visual acuity
feral pigeon
accipeter melanoleucus
Animal Behaviour
Behavioural Ecology
Evolutionary Biology
Population Ecology