| Abstract: | The concept of personality implies individual differences in behavior and physiology that show some degree of repeatability/consistency over
time and across contexts. Most studies of animal personality, particularly studies of individuals' variation in physiological mechanisms, have been
conducted on selected individuals in controlled conditions. We attempted to detect consistent behaviors as well as physiological patterns in greylag
ganders (Anser anser) from a free-roaming flock living in semi-natural conditions. We tested 10 individuals repeatedly, in a handling trial,
resembling tests for characterization of “temperaments” in captive animals. We recorded the behavior of the same 10 individuals during four
situations in the socially intact flock: (1) a “low density feeding condition”, (2) a “high density feeding condition”, (3) a “low density post-feeding
situation” and (4) while the geese rested. We collected fecal samples for determination of excreted immuno-reactive corticosterone (BM) and
testosterone metabolites (TM) after handling trials, as well as the “low density feeding” and the “high density feeding” conditions. BM levels were
very highly consistent over the repeats of handling trials, and the “low density feeding condition” and tended to be consistent over the first two
repeats of the “high density feeding condition”. Also, BM responses tended to be consistent across contexts. Despite seasonal variation, there
tended to be inter-test consistency of TM, which pointed to some individual differences in TM as well. Aggressiveness turned out to be a highly
repeatable trait, which was consistent across social situations, and tended to correlate with an individual's resistance during handling trials. Also,
“proximity to the female partner” and “sociability” – the average number of neighboring geese in a close distance while resting – were consistent.
We conclude that aggressiveness, “affiliative tendencies” and levels of excreted corticosterone and testosterone metabolites may be crucial factors
of personality in geese.
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