Owls, the nocturnal birds of prey belonging to the order Strigiformes, are widely known for hunting small mammals like mice and voles. The answer to whether they eat insects is an unequivocal yes, though the importance of this prey varies considerably across the over 200 species worldwide. For many owls, insects represent a reliable and calorie-rich food source. The consumption of insects highlights the dietary flexibility that allows owls to thrive in nearly every ecosystem on the planet.
Species That Rely Heavily on Insect Prey
For some of the smaller owl species, insects form the primary component of their annual diet. These insectivorous specialists are often diminutive in size, a physical trait that makes them highly efficient at capturing arthropod prey. The Flammulated Owl, for instance, is almost entirely dependent on insects, with its diet consisting mainly of nocturnal species like owlet moths, crickets, and beetles. This migratory bird, only about six inches long, is likely dictated by the seasonal availability of its insect food source.
Similarly, the Elf Owl, the world’s smallest owl, found in the southwestern United States and Mexico, feeds heavily on insects, spiders, and scorpions. These tiny predators employ hunting techniques that differ from their larger relatives, often capturing flying insects mid-air in what is known as a sallying flight from a perch. Various species of Screech Owls and Scops Owls also rely predominantly on insects, particularly during the warmer months when arthropods are abundant. The abundance of these small, protein-filled prey items is a major factor in the successful breeding of these small owl species.
Seasonal and Supplemental Insect Diets
Insects also serve as an important supplemental food source for many larger owl species who are primarily accustomed to mammalian prey. Owls such as the Great Horned Owl and the Barred Owl, which are generalist predators, will opportunistically consume insects based on seasonal availability and local conditions. For the Great Horned Owl, while small mammals account for an estimated 90% of its diet, the remaining portion is a mix of birds, herptiles, and insects.
The consumption of insects by these larger species often peaks during the summer months when ground-dwelling insects, such as large beetles and grasshoppers, are most active and easily caught. This seasonal dietary shift provides a reliable source of protein and fat when typical prey might be harder to find or when the owls are feeding young. Breeding females and growing owlets require high amounts of protein for development, and a surge in insect populations can provide a crucial nutritional boost.
For the Barred Owl, which eats a wide variety of prey including mice, crayfish, and snakes, insects are included in its diverse menu. Analysis of owl pellets frequently reveals the hard exoskeletons, or chitin, of insects even from species that focus on vertebrates. This evidence demonstrates that insects, though a minor part of the diet for some, provide a consistent and overlooked food resource across the entire owl family.