Personality traits and the effects of DHA supplementation in the budgerigar ( Melopsittacus undulatus)

Abstract

We investigated the hypotheses that a bold-shy personality axis exists in the budgerigar ( Melopsittacus undulatus) and that dietary docosahexaenoic acid (DHA) supplementation has a significant effect on budgerigar personality and immune responses. DHA is an integral component of the brain known to impact cognitive function, and its impact on budgerigar behaviour is previously unstudied. Adult budgerigars (14 females, 9 males) were housed in two home pens and received either a control diet or a diet supplemented with DHA. The birds were tested in seven experimental situations designed to gauge boldness. Behavioural responses within the categories of fear, feeding and activity were recorded as well as immune status. Our results suggest that dietary DHA supplementation had no effects on the behavioural and immune variables measured in this study. The results do suggest that budgerigars have bold-shy personality traits for their activity and feeding behaviours, as indicated by significant correlations between percent of locations in the central area of the open field with activity in the presence of the familiar flock in the tendency to flock test ( r S = 0.754, N = 9, P < 0.05), net distance travelled in the open field with activity in the presence of the unfamiliar flock in the tendency to flock test ( r S = −0.812, N = 8, P < 0.05), activity in the presence of the familiar flock and activity in the presence of the unfamiliar flock ( r S = 0.838, N = 10, P < 0.05) and the number of seeds eaten alone and the number of seeds eaten in competition, both in the foraging and competition test ( r S = 0.770, N = 11, P < 0.05). Additionally, significant correlations between open field activity variables and fear variables measuring latencies may indicate that activity and fear variables are related. Finally, although there were several significant correlations between immune parameters and behavioural variables, the results were inconsistent with the hypothesis that immune status and personality are related in the budgerigar. In summary, our results indicate that DHA at the levels used had no effects on budgerigar personality or immune status. However, the results do provide evidence to support the hypothesis that budgerigar personality occurs as a bold-shy axis since budgerigars behaved consistently with regard to activity levels and, for males, feeding behaviour. Females showed a higher innate immunity as measured by the bactericidal activity of whole blood, while in males, this parameter was related to feeding behaviour.