About our lab
The lab’s current research focus is on how diet quality influences cognitive and social behavior in zebra finches, which are obligate graminivores (grass-seed eaters). While it is known that early protein deprivation has deleterious effects on cognitive development in humans and several rodent species, impact of diet on adult performance of birds is largely unstudied. If protein-limitation has consequences for development in relatively large-brained birds, such as passerines, then diet variation may have important influences on cognitive performance and social complexity.
Many, if not most, seed-eating birds supplement their diet with insects or other sources of protein/nutrients, but zebra finches do not. Nevertheless, the protein content of their diet naturally varies considerably: mature grass seed is low in protein and has a restricted range of amino acids, but half-ripe seed has more protein and a broader range of amino acids. Not surprisingly, zebra finches, which are capital breeders (females metabolize breast muscle to produce eggs), prefer to breed when half-ripe seed is available, although they do breed when only mature seed is available if it is sufficiently abundant (Burley et al. 1989; Zann et al. 1995). In the lab we supply boiled hen’s egg, which has an amino acid profile very similar to half-ripe seed.
Our first experimental paper on this topic has established that birds reared on an egg-supplemented diet perform significantly faster on an associative learning task than those reared on mature seed alone. Egg-supplemented birds also developed somewhat different body morphologies, with proportionately larger heads. Regardless of treatment, birds that invest more in head growth (vs body growth) during subadult development perform relatively well on this cognitive task as adults (Bonaparte et al. 2011).
Current research projects in the lab investigate how rearing diet influences reproductive competition in aviary breeding populations and how diet influences male song traits. Questions of interest include: Are birds reared on egg-supplemented diets preferred as mates? Does rearing diet influence mate-getting or mate-retention tactics, extra-pair behaviors, parental behaviors (including tendency to provision egg to offspring), nest site selection or nest building competence? What is the impact of rearing diet on other cognitive skills, such as predator avoidance?
I expect the study of diet effects on zebra finch cognition to make significant contributions to, and provide linkages between, the topics of comparative cognitive ethology, sexual selection, and social evolution. This is a very promising system in which to bridge mechanistic and functional approaches to a range of important questions.