Trophic Level

Birds occupy every trophic level: primary consumers (granivores eating seeds, herbivores grazing grass), secondary consumers (insectivores), and apex predators (eagles, owls). Omnivores such as crows and starlings bridge multiple trophic levels. Biomagnification of persistent organic pollutants and heavy metals intensifies at each trophic step, so apex predators like peregrine falcons and ospreys accumulate the highest tissue concentrations — making them sensitive sentinels of environmental contamination.