Study how laboratory experiments, field observations and removal studies test interspecific competition. Connell's barnacle study links removal experiments to fundamental and realized niches.
In South Korea, flocks of birds of the tit family (Paridae) forage together on trees for food. Researchers observed four species of Paridae to determine whether they shared the same habitat in the trees and whether their position on the tree depended on their size. The leafy part of the tree (crown) was divided into nine sections, three according to height from the ground and three according to the distance from the tree trunk. Observations were also made of birds foraging in the bushes surrounding the trunk and on the ground below the tree. The chart shows the relative use of each section of the habitat by the birds.
Discuss whether the results for the Varied Tit and Coal Tit indicate competitive exclusion.