Can a duck drown? The answer is yes, despite their deep relationship with water. While ducks are highly water-adapted, they are not immune to the hazard of submersion. Drowning is respiratory failure resulting from the inhalation of water. Certain circumstances can overwhelm a duck’s natural defenses, causing it to sink or be forcibly held beneath the surface.
Biological Adaptations That Prevent Drowning
The primary defense against waterlogging and sinking is the duck’s specialized plumage and the uropygial gland, often called the preen gland. Located at the base of the tail, this gland secretes an oily, waxy substance that the duck meticulously spreads over its feathers during preening. This oil makes the feathers water-repellent, preventing the downy underlayer from becoming saturated. Saturation would compromise insulation and buoyancy.
Feathers are also structured to trap air, creating a buoyant layer similar to a built-in life vest. The tiny barbs on the feathers interlock, holding a cushion of air close to the body, which aids in flotation. Ducks possess lightweight, hollow bones, which contributes to their overall low density. Their respiratory system, which includes internal air sacs, also helps maintain buoyancy.
When diving, ducks can compress their feathers to expel some of this trapped air, reducing buoyancy to stay submerged. They also possess a “diving reflex,” which helps manage oxygen consumption. This reflex slows the heart rate and rations oxygen to the central nervous system. These mechanisms allow them to cope with brief periods underwater.
Non-Behavioral Causes of Submersion Fatalities
A duck’s defenses can be rendered useless by environmental factors or physical incapacitation. Loss of the feather’s waterproofing is a common accidental cause of fatality, most notably from oil contamination. When feathers are matted by oil, they lose their ability to repel water and trap air, causing the bird to lose buoyancy and insulation. The duck then becomes waterlogged, which can lead to sinking and subsequent drowning or hypothermia.
Physical exhaustion is another contributing factor, as a severely weakened bird may lack the strength to keep its head above water, especially in turbulent conditions. This is particularly true for ducklings, whose uropygial glands are not fully developed. They are highly susceptible to waterlogging and hypothermia if they remain in the water too long. Physical injury or ingestion of toxins can also prevent a duck from maintaining the muscle control necessary to keep its airway clear.
External restraints, such as entanglement in fishing line, discarded plastic, or other debris, can physically pull or hold a duck underwater. In these scenarios, the bird’s natural ability to swim to the surface is mechanically blocked. Struggling against the restraint combined with the inability to breathe leads quickly to death by submersion.
Drowning Due to Aggressive Social Behavior
One distinct cause of duck drowning is related to intraspecies aggression during the breeding season. Male ducks, particularly Mallards, are known for engaging in highly aggressive forced copulation attempts. This behavior, often involving multiple males, is termed forced extra-pair copulation (FEPC).
During these encounters, a group of males will chase and subdue a female on the water’s surface. The males often take turns mounting the female, forcibly holding her head underwater to prevent her from escaping. The female’s struggle, combined with the weight and force of several males, causes her to be held beneath the surface, leading to suffocation and drowning.
These aggressive mating attempts can result in severe injuries, feather loss, and death by submersion for the female. Studies estimate that in certain Mallard populations, up to 10 percent of females may be killed annually as a direct result of these forced mating attempts. This behavior is a significant, non-accidental cause of drowning.