yellow-headed blackbirds and marsh wrens often occur in the same marshy areas. when they occur together, territory sizes are relatively small with marsh wrens occupying territories at the edge of the marsh, and yellow-headed blackbirds occupying the edges of the ponds at the center of the marsh. in a removal experiment at two different sites, marsh wrens were removed and yellow-headed blackbirds remained. at the second site, yellow-headed blackbirds were removed and marsh wrens remained. at both sites, the territory sizes increased for each species in the regions where the other species is found when they occur together. which statement best reflects which portion of the niche is occupied when both species occur together?
