DOI: 10.5061/dryad.nzs7h4527
title: Data from: Within-flock heterogeneity in exploration affects flock behaviour in a highly gregarious bird

description: How individual differences translate into group outcomes is a
 controversial issue and depends on the phenotypic composition of the
 group. Research on the effect of within-group homogeneity/heterogeneity in
 phenotypic composition provided contrasting results, with some studies
 supporting benefits of homogeneity and others the opposite. We
 characterized a personality trait in a gregarious bird, the European
 starling (Sturnus vulgaris), and investigated how different degrees of
 within-flock variation in exploration affect flock behavioural responses.
 Based on consistent individual differences in exploration, we formed
 flocks of 4 birds differing in mean and variation of exploration scores.
 These flocks underwent an exploration test and a perturbation test to
 assess escape response. We found that, compared to less exploratory
 individuals, more exploratory individuals enter the test room earlier and
 start and stop flying sooner upon frightening (escape response). Flocks
 with a more homogeneous distribution of the individual exploration scores
 are significantly faster to enter the exploration room, but there is no
 clear effect on the escape response. The mean exploration score of the
 flock or the maximum exploration score of purported ‘key’ individuals
 within groups do not explain differences in group performance. The results
 indicate that it may not be the individual that drives the flock
 behaviour, but rather the phenotypic variation within the group, and
 suggest that a homogenous distribution of personality types could speed up
 collective decision-making in gregarious species.
description: VARIABLE NAME and EXPLANATIONS * Line.Nr: Numbering of lines. * Flock.ID:
 Identity of flock, created for flock tests. * Starling.ID: Identity of
 individual starlings. * Test.session: Test sessions, one in 2017, and two
 in 2016 (with an interval of two weeks). * Batch: Batch; one batch
 repeatedly tested in both years, and the other batch tested for the first
 time in the second year. * Ind.test_lat.enter: Individual test: Latency to
 enter room [s]. * Ind.test_N.items: Individual test: Numbers of items
 explored. * Ind.test_perc.t.fly: Individual test: % Time spent flying. *
 Ind.test_perc.t.perch: Individual test: % Time spent on perch. *
 Ind.Expl.score: Exploration score, which is PC1 of a principal component
 analysis based on all variables (including repeated measurements) of the
 individual-based tests. * Dev.ind.Expl.score_within.flock: Deviation of
 the exploration score (see above) from the mean score value of all
 individuals assigned to the same flock. Only calculated for birds
 undergoing flock tests. Thus, for all variables from here on, there are
 only values for the test session in 2017, when the flock tests were
 carried out. * CV_ind.Expl.score_within.flock: Coefficient of variation of
 the exploration score (obtained from individual-based tests) within flock.
 One value per flock. * Mean_ind.Expl.score_within.flock: Mean of the
 exploration score (obtained by PCA from individual-based tests) within
 flock. One value per flock. * Min_ind.Expl.score_within.flock: Minimum of
 the exploration score (obtained by PCA from individual-based tests) within
 flock. One value per flock. * Max_ind.Expl.score_within.flock: Maximum of
 the exploration score (obtained by PCA from individual-based tests) within
 flock. One value per flock. * Dev.log.lat.enter.room_flock.test:
 Within-flock deviation from the mean values of the (log-transformed)
 Latency to enter the room [s] during a flock test (flock exploration
 test). One value per individual of each flock. *
 Dev.log.lat.start.fly_flock.test: Within-flock deviation from the mean
 values of the (log-transformed) Latency to start flying [s] during a flock
 test (flock pertubation test). One value per individual of each flock. *
 Dev.log.lat.stop.fly_flock.test: Within-flock deviation from the mean
 values of the (log-transformed) Latency to stop flying [s] during a flock
 test (flock pertubation test). One value per individual of each flock. *
 MEAN.log.lat.enter.room_flock.test Mean value of the (log-transformed)
 Latency to enter the room [s] during a flock test (flock exploration
 test). Average over all individuals per flock, thus one value per flock. *
 MEAN.log.lat.start.fly_flock.test Mean value of the (log-transformed)
 Latency to start flying [s] during a flock test (flock pertubation test).
 Average over all individuals per flock, thus one value per flock. *
 MEAN.log.lat.stop.fly_flock.test Mean value of the (log-transformed)
 Latency to stop flying [s] during a flock test (flock pertubation test).
 Average over all individuals per flock, thus one value per flock. *
 RANGE.log.lat.enter.room_flock.test Range span of the (log-transformed)
 Latency to enter the room [s] during a flock test (flock exploration
 test). Average over all individuals per flock, thus one value per flock. *
 RANGE.log.lat.start.fly_flock.test Range span of the (log-transformed)
 Latency to start flying [s] during a flock test (flock pertubation test).
 Average over all individuals per flock, thus one value per flock. *
 RANGE.log.lat.stop.fly_flock.test Range span of the (log-transformed)
 Latency to stop flying [s] during a flock test (flock pertubation test).
 Average over all individuals per flock, thus one value per flock.