The word carnivore evokes large predators like big cats and wolves hunting their prey and feasting on the remains. We see them as strong, powerful meat-eaters stalking their prey or hunting in packs. Typically, this means we think of mammalian species.
But what about birds? For example, eagles will also strike down their prey and feast on carcasses, so are birds carnivores too?
Although many birds make up a large proportion of their diet from eating meat, only birds that survive almost solely on meat are called carnivores. Carnivorous birds have four groups: piscivorous (fish eaters,) avivorous (bird eaters,) insectivorous (insect eaters,) and molluscivorous (mollusk eaters.)
We often label animals within these categories based on the main elements of their diets. Carnivores are the meat-eaters. While meat may not make up 100% of the diet, the percentage is substantial enough to separate them from other animals.
This diet tends to apply to those highest in the food chain that feeds on other animals like herbivores. Herbivores rely on a plant-based diet, eating vegetation and grazing. The omnivores have a more varied diet and will eat a mixture of plant and meat-based options depending on what is available.
Are Birds Carnivores?
Some birds do fall into the classification of carnivores because of their diets. However, this isn’t the case for all species. Also, there are distinctions between different types of carnivorous birds depending on their primary food source.
There needs to be a level of variation between bird species to create healthy ecosystems and food chains. If every bird were carnivorous, there wouldn’t be the seed-eaters and nectar drinkers to help plants reproduce and disperse their seeds. If every bird were purely insectivorous or focused on grains, there wouldn’t be the avian apex predators for population control. Each bird has its niche in its environment.
Bird species are classed as carnivorous because of the large amounts of meat and prey items in their diet. Birds that survive almost solely on meat are carnivores. The most prominent group is the birds of prey. Hawks, eagles, owls, and other raptors spend their time hunting for food and are at the top of the food chain.
They often eat small animals such as rodents, rabbits, and other bird species. Studies of remains around nest sites usually provide a fascinating insight into these birds’ diets and their impact on the ecosystem.
Not all carnivorous birds are hunters. Some species feed on carrion instead. Several predatory birds will scavenge for food. This means searching for animals already dead or the remains of kills. Some raptors will take advantage of this via roadkill but tend to hunt their prey.
Fresh meat is preferable to those that have the skills to find it. On the other hand, vultures deliberately seek carrion as an energy-saving alternative to hunting. They can detect gases emitted by decaying bodies long distances and clean up the remains. The carrion crow is another excellent example, getting its name from the activity, but there is more to this bird’s diet. They will also steal eggs and eat small mammals, amphibians, insects, fruit, and seeds.
There are other categories for carnivorous birds depending on the source of meat.
The vast range of bird families and their feeding behaviors means it isn’t enough to separate them between carnivorous or herbivorous species. There are many different sources of meat, leading to distinct diets. These birds can be:
Avivorous birds are those that mainly feed on other birds. Some birds of prey specialize in hunting other birds and provide great population control in an ecosystem – something misunderstood by those that vilify hawks for attacking songbirds in their gardens. Peregrine falcons are also avivores, focusing on pigeons in urban areas and shorebirds around the wetlands.
Molluscivorous birds are those that mostly eat mollusks. Many shorebirds fall into this category as they spend much time feeding on shellfish and other creatures in mudflats and beaches. You will often see masses of birds of various species feeding in the same area. They have evolved differently in feeding so they can coexist and find safety in numbers. Those with long bills will probe deeper while others feed closer to the tideline.
Insectivorous birds are those that rely on insects for the majority of their diet. Flycatchers and swallows are great examples, as they catch insects. Skilled hunters can take larger prey, with many feeding on moths and butterflies. There are also species of falcon that will catch dragonflies over lakes and ponds. Some will also eat them while flying.
Piscivorous birds turn to fish populations as their primary source of food. One example is the heron, which waits by the water and feeds on some larger fish. Their diet is more varied, eating amphibians and mammals, but fish is the primary source. There are also birds of prey that fill this fish-eating niche, such as ospreys and bald eagles. Diving birds out in lakes and oceans will also take their fair share, evolving to become adept underwater.
There are also many omnivorous birds. Insects make up a large part of many bird species’ diets without becoming their primary source. Songbirds are an excellent example of omnivorous species that will take what they can get. There are many seed-eaters among them, and seeds and nuts make up a large part of their menu at bird feeders, but they will also eat mollusks and insects. Mealworms and caterpillars are essential food sources for growing chicks due to their water content.
Many birds are carnivorous to some extent, but not all. While some unique carnivorous bird species exist, not all birds are carnivores. It all depends on the percentage of meat in their diets. Many species, from small flycatchers to massive eagles, are carnivorous in their way, but plenty of omnivores take advantage of what they can find.
Bryan Harding is a member of the American Society of Mammalogists and a member of the American Birding Association. Bryan is especially fond of mammals and has studied and worked with them around the world. Bryan serves as owner, writer, and publisher of North American Nature.