Final answer:
The relationship exemplified by starlings displacing bluebirds from nesting sites is best defined as competition.
Step-by-step explanation:
The relationship exemplified by starlings displacing bluebirds from nesting sites is best defined as competition. In this case, the starlings and bluebirds are competing for the same limited resource, which is the nesting sites. Only one species can successfully occupy the site, and in this situation, the starlings are able to outcompete the bluebirds and take over the nesting sites.
Competition is a common ecological interaction where different species compete for resources like food, territory, or mates. It can occur between individuals of the same species (intraspecific competition) or different species (interspecific competition).
For example, if two lion prides compete for the same hunting grounds, they may have to fight to establish dominance and secure access to food resources.
Learn more about Competition in ecological interactions