Fig. 2.

Testing apparatus for group size preference and social contact. Subjects are placed in a 1m-wide central cage containing seven perches (shown as thin lines). The subject’s location is recorded each 15 sec for 5 min. The percent of test time spent on the two end perches combined yields a measure of social contact (“contact time”). The percent of contact time that is spent next to the large group yields a measure of group size preference (“gregariousness”).