Evaluation of boldness assays and associated behavioral measures in a social parrot, monk parakeet (Myiopsitta monachus)

Abstract

Boldness reflects consistent individual differences in risk-taking behavior across various contexts. However, evaluating this basic assumption has largely been neglected in birds. In a captive monk parakeet population (Myiopsitta monachus; N = 33), we undertook an analysis of 7 measures across 3 commonly used boldness assays (i.e., novel object, emergence, and predator-exposure tests). Using principal component analysis, we derived 3 components (PCs). PC-2 loaded strongly with measures from emergence and predator-exposure tests; we interpreted it as the closest approximation of boldness. PC-1 and PC-3 described different aspects of feeding such as foraging activity and rate, respectively. Finally, we assessed the predictive power of each measure that loaded significantly on the boldness axis. We found that no single metric explained even %55 of the variation in PC-2, nor could more than %50 individuals at the extremes of the spectrum be predicted. Our results demonstrate the utility of an inclusive approach in personality research.

Social conformity affects experimental measurement of boldness in male but not female monk parakeets (Myiopsitta monachus)

“…Given that the study species is intensely social -foraging, roosting and breeding in large flocks and likely keeping relationships with individuals over many years -we sought to evaluate whether boldness measures observed in standard solitary personality tests were consistent with results obtained in a group context. Using the same set of individual birds that were tested in a different year (reported in Kerman et al, 2016), we evaluated the effects of conspecific presence on the same standard risk-taking metrics across three behavioural assays for each sex: novel object, emergence in a new environment, and predator exposure tests. We conducted social assays of boldness where test subjects were accompanied by a pair of companions with mid-level boldness scores (with respect to the study flock), and compared boldness responses between the two social settings in this paper.…”

“…Birds were not allowed to breed in captive conditions. For detailed descriptions of the methodological procedures implemented for trapping, transporting and housing birds, see Kerman et al (2016).…”

“…We used a fixed order, repeated-measures design to compare the behavioural output of individuals previously tested in a solitary setting (results published in Kerman et al, 2016) in the presence of a pair of companion birds (this study). We conducted social assays opportunistically in 2014, approximately a year after solitary measures were collected in 2013.…”

“…On test day (day 5), we placed food plus novel objects within each food saucer, and presented them to focal birds at 0830 h. Only focal individuals received a novel object inside the food saucer; social companions had only food inside the saucer. Novel objects varied from the ones used in the solitary assays published previously (see Kerman et al, 2016). We used a combination of a plastic bag clip and a rubber ring as novel stimulus.…”

“…Emergence and predator exposure tests were conducted in a medium-sized aviary (1.2 × 1.8 × 2.5 m, Figure 2). The aviary was located at a different section of the research facility than the one used in the previous study (see Kerman et al, 2016), and maintained the same dimension and design. We placed eight branches inside the aviary.…”