Meeting Abstract
For birds that overwinter in north temperate zones, such as Black-capped Chickadees and Dark-eyed Juncos, keeping track of reliable long-term food resources is critical. Chickadees have an additional overwintering strategy of storing food in unique cache sites and locating them using memory. Animals and humans have multiple memory systems. While both chickadees and juncos are under selective pressure to remember reliable long-term spatial locations (habit memory), chickadees are under additional selective pressure for quickly forming and rapidly updating spatial memory for unique cache sites (one-trial memory). We conducted a series of touchscreen experiments to assess each species reliance on these two types of memory. Habit memories were experimentally established in trials in which photographic backgrounds were paired with spatial arrays in which the same location always rewarded. In other trials, birds were given one-trial memory tasks on different photographic backgrounds that required them to remember which location had been rewarded most recently. Both species showed high accuracy on these one-trial memory tests. On trials in which one-trial and habit memory were put in conflict, however, both species preferentially used habit memory. We hypothesized that photographic backgrounds provided a contextual cue that birds used to determine which memory system to use. In a further experiment, the same photographic backgrounds were used for both habit trials and one-trial memory trials, eliminating their utility as a contextual cue. This change in procedure increased the use of one-trial memory and decreased the use of habit memory on trials in which the two memory systems were in conflict. We discuss how ecology and context influence the use of memory systems in Black-capped Chickadees and Dark-eyed Juncos.
