Does innovation indicate behavioral flexibility? Bird brain was considered an insult until a recent discovery that bird brains have an area that performs functions similar to that of the mammalian neocortex (the cognitive processing center). Researchers have begun looking for, and finding, avian intelligence in the large-brained species: crows make and use tools, rooks cooperate to get food, and western scrub-jays plan for the future. But is such intelligence restricted to species with large brains? Innovations (novel foraging techniques) are assumed to indicate behavioral flexibility (which is assumed to be a form of complex cognition) and the number of innovations a species has increases with relative brain size. This project investigates the link between innovation and relative brain size (corrected for body size) in a non-innovative bird with an average relative brain size, the great-tailed grackle (Quiscalus mexicanus). I compare grackle cognitive performance with that of innovative, large-brained New Caledonian crows (Corvus moneduloides) to test this assumption and begin to elucidate the benefits provided by large brains. I conduct additional behavioral, genetic, and immune system research on grackles in the wild to understand how and why their cognitive abilities evolved. Investigating how these abilities are used in their daily lives will indicate which factors shaped their intelligence.
What to do after a fight? Post-conflict affiliation (social support) in birds Conflicts are part of social life and many species employ conflict resolution strategies to maintain relationships with group members. One strategy is to engage in social support after the fight (post-conflict affiliation), which can occur between the individuals that fought (former opponent affiliation) or between a former opponent and a bystander (third-party affiliation). Our aim was to compare three closely related birds in the crow family (rooks, jackdaws, and Eurasian jays) to determine how the presence of strong social bonds influences post-conflict affiliative behavior. We found that the species with strong pair bonds year-round (rooks and jackdaws) engaged in post-conflict third-party affiliation with their mates after fighting with another group member (mates never fought with each other). In contrast, the Eurasian jays did not have strong bonds with their mate outside of the breeding season when their data were collected and, thus, engaged in post-conflict third-party affiliation with any individual not involved in the conflict. These results relied on our expansion of the methods for studying post-conflict affiliation. Post-conflict affiliation was not detected in any species according to the traditional measure (affiliation must occur sooner after the conflict than in the matched control condition), however there were higher frequencies and durations of affiliation after conflicts in all three species. The use of affiliation after conflicts may function to reduce stress, however further studies will be needed to investigate this.
Do army ant-following birds remember the past to plan for the future? We discuss a rarely studied bird behavior and propose it as a good system for the study of mental time travel, the ability to remember the location and time of an event that occurred in the past and then use this integrated memory to imagine future choices. Some tropical birds collect their prey at army ant raids, where massive swarms of ants sweep through the forest and drive out insects. The behavior of interest is called bivouac checking; it allows these birds to track the cyclical raid activity of army ant colonies. Army ants have regular alternating periods of high and low raiding activity, and birds visit the antsí temporary nest sites (bivouacs) to determine which colonies are raiding on a given day. We suggest bivouac checking allows birds to keep track of multiple army ant colonies, keeping account of which colonies are in periods of high raiding activity while avoiding colonies with low raiding activity. Birds check army ant bivouacs at the end of the day after they have fed at the raid. They may use the information about the army ant nest location the next day to find the ants again, thus accessing a past memory (the nest location) to fulfil a future need (bird will be hungry tomorrow). We provide a framework for investigating this behavior in the field and lab to determine whether it is a candidate for mental time travel.