Interspecific competition in its most basic form is defined by the presence of at least two different species living concurrently that compete for one or more of the same resource (Smith & Smith, 2014). That being said, there are other conditions that should be present before concluding that interspecific competition is present in an ecosystem. For one, in order for there to be true competition, the resource in question needs to be in such limited quantity as to determine a "winner" between the different species; the species cannot both equally "win" per the competitive exclusion principle (Smith & Smith, 2014). Additionally, the competition must be able to be measured/modeled by Lotka-Volterra Model (Smith & Smith, 2014). Some observations of species interaction that I've seen in my time living in the suburbs of the Greater Phoenix Area are mourning doves and grackles fighting for food and different ornamental shrubs such as bougainvillea and oleander vying for space in a garden patch. The birds fighting for food - whether natural or human-provided - is almost certainly competition, but the bougainvillea and oleander could potentially be simple coexistence rather than competition, as I often see both growing equally as healthy when I do see them growing side-by-side