Describes a diet that consists primarily of insects, including aquatic insects, flying insects, ants, spiders, grasshoppers, caterpillars, dragonflies, butterflies or any combination of similar prey.
Also Known As
Insect-Eating, Insectivore (noun)
Many birds have at least a partially insectivorous diet, and insects are a critical source of protein for many growing nestlings. While young birds are still dependent on their parents for food, they may be fed mostly insects, even if their mature diet will be much different. To be considered insectivorous, a bird does not necessarily need a diet of exclusive insects, but the insect proportion is quite significant.
Birds that are primarily insectivorous throughout their lives include:
Many additional birds eat a great variety of insects, including small birds of prey such as screech-owls and kestrels. Hummingbirds and other insectivorous birds also eat a large number of insects to provide protein in their diets.
Birds may also change their diet throughout the year. For example, many thrushes are primarily insectivorous during the breeding season when chicks need more significant amounts of protein and insects are abundant. This protein is also essential for molting adults for new feathers to develop properly. In fall and winter, however, these birds may switch to more of a frugivorous diet when insects are scarce, but autumn fruits are still plentiful.
Foraging for Insects
Insectivorous birds forage in different ways. They may catch insects in flight or pick them from plants, leaves, water or leaf litter. Small birds are often seen hawking or sallying, foraging methods that involve small, hovering flights to pluck insects before returning to a nearby perch. Birds that are agile climbers, such as woodpeckers, nuthatches, and creepers, will glean insects from bark and branches. Many shorebirds and wading birds will probe through mud or sand in search of insects, while ducks may dabble or dive to find insects. Small birds of prey, such as the American kestrel, will hover or soar to find large insects in open fields or may perch far above the ground to watch for insect prey with their keen eyesight.
Insectivores in the Backyard
Backyard birders can attract insectivorous birds by avoiding the use of insecticides and pesticides on their landscaping. As birds visit the yard, they will provide natural insect control as they feed. Many birds will also use spider silk as nesting material, which is another excellent reason for birders to keep insects in the yard.
Offering fresh or dried mealworms at bird feeders can also be a treat for insectivorous birds. This can be particularly effective after baby birds have hatched when parent birds are hard at work to feed a hungry brood and may visit feeders repeatedly for mealworms. Some suet blends are also made with insects such as crickets, flies, and mealworms.
In addition to birds, many amphibians and reptiles are also insectivores.