Within-flock heterogeneity in exploration affects flock behaviour in a highly gregarious bird

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 homogeneo..., , , 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 underg...,