Meeting Abstract
Cognition is important for foraging because individuals can learn and remember profitable sources of food. However, cognition is not the only way to find food. Particularly in group living species, some individuals may successfully forage by scrounging from others. Both tactics may be effective, but there are likely trade-offs in their expression because both cognitive ability and competitive scrounging entail high developmental costs. However, few studies have investigated individual variation in cognitive ability and scrounging, and trade-offs between these traits, in wild populations. We measured individual learning speeds and scrounging rates in large mixed-species flocks of 3 songbird species: great tits, blue tits and marsh tits. We used arrays of bird feeders that were programmed so that each individual was only able to access food in one of the five feeders at an array. We measured the speed to learn to use the rewarded feeder as well as rates of scrounging at the non-rewarded feeders. Individuals that scrounged more often were slower to learn the task, suggesting a trade-off between cognition and scrounging. Blue tits scrounged more than the other species, perhaps because they were less competitive in accessing their own rewarded feeder. Nevertheless, scrounging behavior was not repeatable. In reversal learning experiments, birds tended to scrounge more at previously rewarding feeders, but did not preferentially scrounge from other birds that had also been assigned to that feeder. Our results reveal a fundamental trade-off between foraging strategies based on learning and scrounging, but the drivers of individual variation in these traits are complex and additional experimental studies are needed to determine how these strategies are related.
