The Northern Cardinal is a familiar sight in backyards across North America, recognized for the male’s striking red plumage and distinctive song. While often seen at feeders cracking seeds with its stout, conical beak, the cardinal’s diet is far more diverse than just plant matter. These birds are opportunists that actively seek out and consume animal protein, revealing that insects are a significant part of their overall nutrition.
The Cardinal’s Omnivorous Diet
The Northern Cardinal is classified as an omnivore, meaning its diet includes both plant material and animal matter. Seeds, grains, and fruits form the bulk of its year-round food intake, especially during colder months. Insects and other invertebrates play an important role as a nutritional supplement. Plant matter can constitute up to 90% of the diet, particularly in winter when insects are scarce, with the remaining portion consisting of animal prey. This vegetable matter includes weed seeds, waste grains, leaf buds, and wild fruits like berries and grapes.
The bird’s robust bill is well-suited for crushing the hard shells of seeds, which are high in carbohydrates and fats. The seasonal shift in food availability and the changing metabolic needs of the cardinal necessitate a flexible approach to foraging. This adaptability allows the species to thrive in diverse habitats, from dense woodlands to suburban gardens, ensuring a steady supply of energy. The inclusion of arthropods, even as a smaller percentage of the overall diet for adults, is a consistent pattern.
Specific Insects Targeted and Foraging Methods
Cardinals actively hunt a variety of insects and small invertebrates. Their prey includes beetles, grasshoppers, crickets, and true bugs. They also consume soft-bodied invertebrates like caterpillars, moths, snails, and spiders, which are easier to process than hard seeds. Consuming agricultural pests, including boll weevils and cutworms, contributes to their reputation as beneficial birds.
The Northern Cardinal employs specific techniques to find and capture these small animals. They are primarily ground-foragers, hopping through low bushes, thickets, and on the forest floor. They glean insects from foliage and leaf litter, using their strong legs and bills to flip over leaves and debris to uncover hidden prey. While they do not engage in sustained aerial pursuit, cardinals are capable of short chases to catch flying insects or snatch them directly from plants and branches.
Essential Protein for Nestlings
The consumption of insects becomes significantly more important during the breeding season when adult cardinals are raising young. Newly hatched nestlings require a diet that supports rapid growth, which is not possible with the lower protein content of seeds. Insects provide concentrated protein and fat, essential for the development of muscle, bone, and feathers.
Both parent cardinals switch their focus to provisioning their young almost exclusively with soft-bodied insects and arthropods. This includes caterpillars, insect larvae, and spiders, which are easily digestible for the nestlings’ undeveloped systems. Parents forage intensely during the 9 to 11 days the young are in the nest, and after they fledge, to meet this high nutritional demand. This reproductive necessity illustrates the dependence of the cardinal life cycle on insect protein.