Final answer:
As flock size increases, individual birds benefit by spending less time on vigilance due to the shared responsibility of predator detection in the larger group. This 'many eyes effect' allows individuals more time for foraging, which is an advantage of larger flocks. However, the exact advantages may vary depending on the species.
Step-by-step explanation:
There is indeed an advantage to individual birds as flock size increases. The primary benefit lies in the decreased necessity for each bird to be vigilant, as they rely on the collective vigilance of the flock for predator detection. This phenomenon is known as the 'many eyes effect', where each individual can allocate less time to predator detection and more time to foraging and other activities, because the larger group size implies that there will likely always be some individuals on the lookout for danger.
This does not necessarily lead to each individual being more vigilant; rather, it allows for a shared vigilance that benefits all members of the flock. Therefore, the correct answer to the student's question would be:
- a) Yes, because each individual has to be more vigilant.
- b) No, because each individual spends less time looking for predators.
- c) It depends on the species.
- d) There is no clear advantage.
- e) Both a and c.
While the general trend shows that larger flock sizes can lead to such benefits, it must be noted that there could be species-specific behaviors that might affect whether increased vigilance or other factors play a significant role. Therefore, the most accurate answer would generally be a) but also recognizing that e). the dependency on specific species could also be a factor.