At first glance, a mallard duckling raised by loons would seem to be in a pickle. When your parents dive and you do not, you spend many anxious moments waiting on the surface. Furthermore, when you instinctively prefer to spend time in the shallows, and your folks prefer open water, you must tolerate their habitat preference as best you can, while nervously peering under water a bit more than usual.
These minor sources of stress seem tolerable for the Long Lake loon-duckling. As it turns out, there are benefits to having two parents assiduously stuffing food into you instead of one parent merely leading you to foraging areas.
You see, when we first observed that a loon pair had adopted a duckling, we were unsure how the duckling might be getting food. We could see that the duckling was healthy and strong — that it continued to grow and thrive. How, we wondered, was a dabbling duck that evolved to pluck and consume small, squishy invertebrates from the shallows surviving with two parents determined to feed it long, rigid, scaly items captured from the deep?
As we can see from Elaina’s stunning photos, the duckling’s solution has been to accept the proffered scaly items — though only small ones that do not pose a swallowing hazard — and to supplement this steady vertebrate diet with bits of animal and plant material gathered on the fly. To look at the bird, this duel feeding mode provides a favorable balance. The adoptee has matured rapidly from a tiny fuzzball into a strapping individual fast approaching adult (duck) size.
While it is physically healthy, the duckling’s mental state is less clear. This bird is a living, breathing test of nature vs. nurture. If the duckling behaves as genes dictate, it will soon join others of its species in huge foraging groups that congregate on lakes at this time of year. But it is thoroughly imprinted on its loon parents, not on mallards. If it has lived too long as a loon chick, it might attempt to associate with that species. Even in this worst case scenario, all is not lost, I think. Full grown mallards, even those that evince inappropriate affection for loons, know that they must bolt when a loon comes stalking them.