Gulls are a familiar sight in coastal and inland environments, recognized for their adaptability and often aggressive behavior. These birds, commonly called “seagulls,” possess a highly varied diet that allows them to thrive in diverse settings. The answer to whether these adaptable flyers prey on other birds is definitively yes. Gulls consume the eggs, nestlings, and even adult individuals of other avian species, underscoring their role as flexible predators and scavengers.
Gulls as Opportunistic Generalists
The foundation of the gull’s feeding success is its nature as an opportunistic generalist, exploiting almost any available food source rather than specializing in one type of prey. Their typical diet includes a wide array of marine and terrestrial items, such as marine invertebrates, small fish, and terrestrial arthropods like insects and earthworms.
Gulls are highly efficient scavengers, consuming carrion, offal, and discarded human refuse. This non-selective, omnivorous approach allows them to include avian prey in their menu. This flexibility ensures their survival, allowing them to rapidly switch to whatever resource is locally abundant when preferred food items are scarce.
The Direct Answer: Avian Prey in the Gull Diet
Gulls consume other birds, primarily targeting avian eggs and nestlings due to their defenseless nature and high nutritional value. During the breeding season, gulls regularly raid the nests of other seabirds, consuming eggs whole or targeting newly hatched chicks. This predation is a significant source of mortality in colonies of species like terns and murres, particularly when the colony is situated near a gull nesting site.
Predation on fully grown birds is less common but occurs, especially with the largest species, such as the Great Black-backed Gull. This apex predator is known for its formidable size and powerful beak, which it uses to hunt birds as large as puffins, grebes, and smaller songbirds. Studies have found that birds constitute a substantial portion of the Great Black-backed Gull’s diet.
Strategies for Avian Acquisition
The acquisition of avian prey involves a spectrum of behaviors ranging from opportunistic scavenging to active, aggressive hunting. One primary mechanism is nest predation, where gulls systematically patrol nesting colonies, seizing eggs or vulnerable chicks left unattended by parent birds. This focused raiding behavior is most intense during the peak hatching period of other species when young prey is abundant and easily accessible.
Gulls also acquire bird remains through scavenging, consuming the carcasses of birds found as roadkill or those that have succumbed to disease, injury, or natural causes. This is an opportunistic behavior, utilizing available protein without the energy expenditure of a hunt.
The most aggressive strategy is active hunting, which involves targeting young fledglings, sick, or injured adult birds that are physically unable to escape. Another specialized method is kleptoparasitism, or food piracy, where a gull aggressively harasses another bird until it drops or regurgitates its freshly caught meal. In cases of direct physical attack, gulls have been observed stabbing the victim with their bill and violently shaking it to dispatch the prey.