The consumption of other birds is a documented part of avian ecology. Birds eat other birds through three primary mechanisms: active predation, where one species hunts another; cannibalism, which involves eating a member of one’s own species; and opportunistic scavenging, which is the consumption of already dead avian remains. This demonstrates that for many species, other birds represent a viable food source.
Active Predation of Other Avian Species
Many bird species, known as avivores, specialize in hunting and consuming other birds as a regular part of their diet. These predators possess specific physical adaptations and sophisticated hunting techniques tailored to catching fast-moving prey. Raptors such as falcons and hawks are the most recognized interspecies bird hunters, demonstrating incredible speed and agility.
The Peregrine Falcon is famous for its “stoop,” a high-speed dive used to strike and often kill flying birds like pigeons and ducks in mid-air. In contrast, Accipiter hawks, including the Cooper’s Hawk and Northern Goshawk, are built for agility. They feature short, rounded wings and long tails that allow them to ambush prey within dense forest and brush. These hawks rely on stealth and rapid maneuverability to capture smaller birds in confined spaces.
Generalist predators also frequently target birds, sometimes with specialized hunting behaviors. Shrikes, often called “butcher birds,” are passerines that use their hooked bills to kill small birds and mammals, often impaling them on thorns or barbed wire to store for later consumption. Certain large gulls, like the Great Black-backed Gull, are known predators that target the eggs, chicks, and even the adults of smaller seabirds.
Cannibalism and Infanticide Within Bird Populations
Cannibalism, the consumption of one’s own species, occurs across many bird groups, often driven by intense resource competition or reproductive strategy. This behavior frequently follows infanticide, the killing of eggs or young, which is observed in territorial and colonial species. Cannibalism provides the surviving individuals with direct nutritional benefits, while infanticide reduces competition for food or eliminates genetically unrelated offspring.
In colonial nesting birds like gulls, pelicans, and boobies, adults may consume unattended or weak eggs and chicks. Among raptors, siblicide followed by cannibalism is a documented occurrence. Parents sometimes facilitate this by feeding the remains of a deceased nestling to its stronger siblings. This acts as a form of brood reduction, ensuring that limited resources are funneled to the most viable offspring.
The behavior is also common in domestic fowl, such as chickens, where it is often a response to stress and poor husbandry conditions. Factors like overcrowding, excessive light intensity, or nutritional deficiencies can trigger feather pecking, which can escalate to the consumption of skin and tissue. A specific form, “vent pecking,” occurs when a chicken pecks at the exposed tissue of a flock mate immediately after an egg is laid, which can quickly lead to fatal consumption.
Opportunistic Feeding and Scavenging Behavior
Many bird species consume avian remains opportunistically, a behavior distinct from active predation or planned infanticide. Scavenging involves utilizing an already deceased bird as a food source, which conserves the energy that would be spent on hunting. Obligate scavengers, such as vultures, rely heavily on carrion and will consume any available dead animal, including birds, playing a significant role in ecosystem sanitation.
Facultative scavengers, which hunt live prey but readily consume carrion, also frequently utilize dead birds. Bald Eagles, for example, are highly opportunistic feeders whose diet includes a significant percentage of birds. They often obtain these as dead carcasses or through kleptoparasitism, by stealing a catch from another animal. Corvids, including crows and ravens, are generalist feeders known for their intelligence and flexibility, allowing them to capitalize on avian roadkill or other found carcasses.
Even smaller birds, like various shorebirds and gulls, will opportunistically feed on avian remains, particularly when their preferred food sources become scarce due to environmental changes or harsh weather. This behavior is motivated by the ease of acquisition, as a deceased or severely injured bird represents an energy-rich meal that requires little effort to secure. The consumption of other birds is not always a violent act of hunting but a pragmatic use of an available resource.