DOI: 10.5061/dryad.79cnp5hvs
title: The anti-predation benefit of flash displays is related to the distance at which the prey initiates its escape

description: Flash behaviour is widespread in the animal kingdom and describes the
 exposure of a hidden conspicuous signal by an otherwise cryptic individual
 as it is fleeing from predators. Recent studies have demonstrated that the
 signal can enhance survivorship by leading pursuing predators into
 believing the flasher will also be conspicuous at rest.
  Naturally, this illusion will work best if potential predators
 are ignorant of the flasher’s resting appearance. One way in which this
 could be achieved is by the prey fleeing when the predator is far away. To
 test this hypothesis, we compared the survival of flashing and
 non-flashing computer-generated prey with different flight initiation
 distances (FIDs) using humans as model predators. This experiment found
 that flash displays confer a significant survivorship advantage only to
 those prey with a sufficiently long FID that the predator has
 little opportunity to view them at rest. A complementary
 phylogenetic analysis of Australian bird species supports these results:
 after controlling for body size, species with putative flashing signals
 had longer FIDs than those without. Species with putative flashing signals
 also tended to be larger, as demonstrated in other taxa. The
 anti-predation benefit of flash displays is therefore related to the
 nature of escape behaviour.
description: We provide two data sets.  The data set in
 <b>FlashGameData</b> represents the responses of 30 human
 participants playing our flash display game.  Each participant was given a
 unique identifier (ID).  Eight virtual prey were used in training followed
 by four virtual prey as test treatments. The prey were presented
 sequentially and in a random order (Order). The colour of the prey when at
 rest (Stationary) and when fleeing (Mobile) is given. Human subjects
 “disturbed” the virtual prey when their mouse cursor moved within a
 certain reactive distance (React, measured in Twips) of the prey, at which
 point the prey fled off the screen through a directed random walk. Our
 subjects were then invited to follow the fleeing prey into a new
 screenshot where the prey may have settled.  Three of the training prey
 were invisible in the settling stage (Visible = 0) making them impossible
 to find. Subjects searching for the settled prey could then either click
 on the prey if they saw it (Attack = 1), or if they could not find it,
 press the "give up" button (Attack = 0).  The time in seconds
 taken for each human subject to either attack the prey item or press
 "give up" is given by TimetoAct.   The data
 set in <b>BirdClassificationData</b> represents the
 classification of Australian bird species as to whether (1) or not (0)
 they were judged by human observers (n = 30) to have hidden colours that
 are only exposed in flight.  Observers were interviewed separately in a
 randomized block format (3 blocks of 10 subjects) with each block having a
 unique presentation sequence.  Here we give the bird species, their mean
 FID in metres (from Blumstein DT. 2003 J. Wildl. Manag. 67, 852 – 857),
 and their mean mass in grams.  The final columns refer to the % of
 subjects that agreed on the most popular classification and show the modal
 classification of a subset of bird species where there is 100%, 90%, 80%
 and 70% agreement.