The personalities of birds such as hihi can be affected by their diet as chicks in the nest, according to research by Massey University PhD student and Hihi Specialist Group member Kate Richardson.
The latest chapter in Kateâ€™s PhD thesis, which she is in the process of writing up, is entitled â€˜Personality in hihi: the role of the early environment and influence on life history traitsâ€™.
Kate writes that, â€˜Studies of animal personality have traditionally viewed (and indeed defined) personality as a relatively rigid trait determined by the genetic makeup of the individual, with some [ability to change in response to their environment]. The role of their [physical development] has received relatively little attention, yet recent work indicates the early environment may play a stronger role in the development of personality than previously thought.â€™
Her experiment investigated the effect of experimental nutrient supplementation to nestlings on their personality traits as young free flying hihi (up to three months after leaving the nest). 99 juvenile hihi were tested in-situ to measure five personality scores: activity, acclimation time, exploration, fear of new objects and ability to escape.
These birds had either been raised on protein with or without carotenoids or sugar with or without carotenoids as nestlings. Kate writes, â€˜We investigated the effect of this supplementation on personality traits as juveniles, and then how these personality traits influenced longer term survival and also natal dispersal (the distance moved from your birthplace to where you settle as a breeding adult).â€™
Her study found â€˜strong evidence that the early [nutritional] environment influences the development, or expression, of personality traits, and demonstrated that these effects are sex-specific. â€˜Juveniles that received carotenoid supplementation in the nest were less concerned about [new situations] than those that did not, and juveniles that received protein supplementation in the nest had lower activity scores.
â€˜Males had longer acclimation times, and females had higher exploratory scores. Individuals which had difficulty dealing with new situations had lower survival probabilities that persisted up to three breeding seasons later, but we did not find strong evidence that personality influenced natal dispersal.â€™
Kate concluded that the results were significant as they demonstrated a successful test of personality that could be carried out quickly in-situ and also provided strong evidence â€˜showing the importance of early natal nutrition in the development and expression of personality traits.â€™
Keep an eye out for Kateâ€™s work as she progresses through writing and publishing her PHD. Regular updates will be provided via our newsletter so please subscribe and/or follow news updates on our twitter feed @hihinews