Signalers do not simply repeat the same exact signal over and over, but rather vary characteristics of the signal. In the case of signaling to attract mates, this variation is often related to changes in competition levels: individuals adjust their signals to remain competitive and attractive as the competition increases. We are interested in the strategies used by animals to assess and respond to changes in social competition. In particular, we are interested in how competition may force animals to make trade-offs between different signal characteristics or functions. For instance, a study of competitive signaling in gray treefrogs showed that there is an upper limit to the ability of males to maximize two different parameters of their advertisement calls. Furthermore, males are often faced with the dilemma of signaling to attract mates and producing more aggressive, but less attractive, signals to ward off competitors. We plan to continue this work by examining the energetic costs of different signaling strategies to identify a mechanistic basis for these trade-offs.
Plasticity is also an important consideration in our studies of animal cognition. Some animals are able to easily learn a task, yet once they learn it they are relatively inflexible if the “rules” change. Other animals are slow to learn but then exhibit rather fast reversal learning. This was studied in a wild population of great tits in which the spatial learning abilities of individual birds were monitored using programmable RFID equipped birdfeeders. This study revealed individual variation in spatial learning ability and related it to reproductive success, providing a rare example of an investigation of the fitness consequences of variation in cognitive abilities.