Yellow-headed and red-winged blackbirds live in marshes. both species can nest in the emergent vegetation in the marsh. if both species are present, the red-winged blackbirds are pushed into the shallower, drier areas on the outer limits of the marsh. what niche are the red-winged blackbirds using when the yellow-headed blackbirds are in the marsh?
a. classical
b. fundamental
c. competitive
d. realized
e. ecological