Question

A group of researchers is collecting data on the foraging patterns of a population of wagtail birds, which feed on an insect called the dung fly. These graphs show some of the data collected by the team:

Given the data presented in each of the graphs, what conclusion can you draw from this data about the feeding practices of the wagtail birds?

Answer 1

We have that the first graph shows that the wagtails take more calories per second when they eat dung flies of length 7mm, since that is the peak. Thus, it would make sense for wagtails to eat these flies. The second graph shows that this is indeed the case, namely most birds choose this length of flies, especially given the number of available flies. This showcases natural selection; birds that chose other lengths had a disadvantage since they needed more time to get their required calories.