White-breasted nuthatches and Downy woodpeckers both eat insects that hide in the furrows of bark in hardwood trees. The Downy woodpecker searches for insects by hunting from the bottom of the tree trunk to the top, whereas the white-breasted nuthatch searches from the top of the trunk down. These hunting behaviors best illustrate which of the following ecological concepts?
A) competitive exclusion
B) resource partitioning
C) character displacement
D) keystone species
E) bottom-up and top-down hypotheses
