This short paper describes a simple agent system aimed at addressing the food gathering problem set for the 2005 CLIMA contest. Our system is implemented as a collection of reactive agents which dynamically switch between a number of behaviours depending on interaction with their environment. Our agents maintain no internal representation of their environment and operate purely in response to their immediate surroundings. The agents collectively map the environment co-operating indirectly via environmental markers and they use these markers to assist them in locating the depot when they discover food. The required behaviour emerges from the interaction between agents and the marked environment. Despite the simplicity of the agents and their behaviours formal description is difficult. We concentrate more on identifying interesting problems in characterising system exhibiting emergent behaviour and outline possible logic approaches to dealing with them.