reeds means a slower growth rate and a longer period of being a size vulnerable to predators, for maximum survival sunfish choose to remain in the reeds feeding on plankton until they reach a certain size and then leave to feed on benthos. Nocturnal animals alter the timing of their foraging based on the level of light – avoiding feeding when the moonlight is bright as this is when predation risk is highest. A raised head is the most commonly used indicator of vigilance, as many animals require their heads to be lowered to search for and handle food. Different foods require different handling that can affect the amount of vigilance an animal can maintain. Seeds without husks, for example, require little handling by birds so are rapidly pecked up with the birds head down which is incompatible with vigilance. In situations of high predation risk, animals may choose foods that can be foraged while maintaining vigilance. When dark-eyed juncos (Junco hymenalis) feed in small flocks, they prefer to feed on larger pieces of food than when they are part of a larger flock. As individuals in smaller flocks have a greater need to be vigilant (see more in Vigilance in groups), large pieces of food are more beneficial as they require a longer handling time that can be simultaneously spent scanning, whereas birds feeding on small pieces must intermittently stop foraging to scan their environment. Vigilance in groups Both solitary and group foraging come with a variety of costs and benefits but for many animals, foraging in a group is the most optimal strategy. Among the many benefits of group foraging, reduction of predation risk by improved vigilance is one. Wood pigeons (Columba palumbus) in large flocks are more able to escape predation by goshawks because they are able to spot them and fly away more quickly than they would individually. This is because in larger flocks, it is more likely that one bird will notice the hawk sooner and alert the group by flying away. Group foraging Advantages A group of animals may be better at both finding and capturing food than solitary animals. For species that feed on food that is patchy, the likelihood of locating food is greater if individuals search for food independently and inform the rest of the group when a food patch is found. Information sharing in this way has little cost to