by John Coluccy, Ph.D.
Those of us who are parents have mixed memories of changing diapers and being awakened in the middle of the night by a screaming baby. But imagine yourself trying to look after four, eight or even a dozen babies all at once, and in a predator-filled environment. This is exactly the situation adult waterfowl face every year. As you can imagine, brood care among waterfowl is a daunting yet critical task.
Adult waterfowl provide their young with many types of care, and the investment in this care varies by species and even individuals. When they hatch, for example, most waterfowl are unable to thermoregulate (keep warm by automatically regulating their body temperature) for several days and periodically require a parent (the hen, in most duck species; both parents in the case of geese and swans) to cover them with their body and wings to help maintain normal body temperature. This behavior, known as brooding, also protects young waterfowl from extreme precipitation (including rain, hail and snow), sunlight, wind and from predators.
Another critical form of care is protection from predators. Most waterfowl utter alarm calls at the first sign of approaching danger. Alarm calls will either cause young birds to scatter, move closer to their parent(s), or freeze in place. Females of many duck species will also feign injury by acting like their wing is broken to draw predators away from their broods. Adult geese may actually attack intruders (including humans) who come too close to their offspring.
Another important role parent birds play is ensuring undisturbed access to feeding and loafing areas. After the young birds hatch, the parent(s) assist their young in finding suitable habitat with adequate food supplies. Sometimes, several broods will use the same wetland, however, and although females tend to avoid one another, contact among broods frequently occurs. In these instances, parents will aggressively defend the area immediately around their brood and attack individuals that come too close.