The sight of a goose attacking and killing a baby duck is common in wetlands and urban parks, often leading people to conclude that geese are predators. This violent behavior suggests a simple predatory relationship where the larger bird hunts the smaller for food. Understanding this interaction requires distinguishing between predation, which involves hunting and consumption for sustenance, and lethal aggression. The true nature of this behavior is rooted in the goose’s biology and seasonal patterns.
Geese Diet: Herbivores, Not Hunters
Geese are classified as herbivores, meaning their diet consists predominantly of plant matter. Their primary food sources include grasses, roots, stems, seeds, and various aquatic plants, which they graze on in fields and shallow water.
The goose’s anatomy is specifically adapted for a plant-based diet. They possess a serrated bill designed for tearing and clipping vegetation, not for capturing animal prey. Their digestive system is optimized to break down complex plant materials like cellulose, often with the help of a diverse microbial community.
Geese consume small invertebrates, such as insects, snails, or worms, incidentally to supplement protein intake, but this is not true predation. They lack a raptor’s hooked beak or specialized stomach enzymes required to digest the meat of a fellow bird. This definitively rules out the consumption of a baby duck as a food source, confirming the killing is not motivated by hunger.
The Reality of Lethal Aggression
Frequent attacks on ducklings are driven by extreme territoriality and the instinct to protect their genetic line. Geese exhibit heightened aggression during the spring breeding season, corresponding with hormonal surges. This seasonal shift transforms the birds into fierce defenders of their nesting sites and newly hatched goslings.
A goose views any nearby small, vulnerable water bird as a potential threat to its offspring or as competition for resources. The aggression is not a hunt but a defensive or preemptive attack aimed at eliminating perceived danger. Male geese, or ganders, are particularly aggressive during this time, actively patrolling the area around their family unit and nest.
The method of attack is brutal and often fatal, focusing purely on neutralization, not consumption. A goose will repeatedly peck, bite, and strike the duckling with its wings, often driving the smaller bird underwater. Sustained trauma and drowning are the typical causes of death for the duckling.
On occasion, geese may try to “steal” the duckling, attempting to incorporate the young bird into their own brood, a behavior seen in territorial waterfowl. Regardless of the motivation, the deceased duckling is consistently left uneaten. This confirms the act was one of behavioral defense and territorial assertion, not predation for sustenance.