Hooded Merganser

This attractive little duck of beaver ponds and other sheltered wooded wetlands breeds throughout New Hampshire. Like the Wood Duck with which it shares habitat, it is a cavity nester, and takes readily to nest boxes provided for this purpose. After significant declines following European settlement and expansion, Hooded Merganser populations have been showing slow but steady declines across the Northeast, as shown both by coarse estimates of numbers (Breeding Bird Survey and Christmas Bird Count) and distributions measured by Breeding Bird Atlases.

Cavity-nesting ducks commonly practice brood parasitism, wherein a female will lay her eggs in another duck’s nest. In the case of Hooded Mergansers, the host is often another “Hoodie” or a Wood Duck, and less commonly a goldeneye or Common Merganser. In areas where Wood Ducks are common, close to half their nests might contain one or more merganser eggs in some years. If the merganser eggs hatch in synchrony with the host eggs the chicks have a good chance of survival and will follow their “adoptive” mother around until they are independent. This contrasts with brood parasitism in songbirds, where hosts generally fail if they are the victim of a parasite like a Brown-headed Cowbird.

Another interesting interspecific aspect to Hooded Merganser biology is the frequency of hybrids with other species of ducks. Hybrids are not uncommon among waterfowl, and one can only wonder if it might result from young imprinting on the wrong species following parasitism. The most common hybrid combination involving Hooded Merganser is with Common Goldeneye, followed by Bufflehead, both of which are closely related to mergansers. Hybrids with Wood Duck have also been reported but they are rare. Note that all of these are other cavity nesters, lending some credence to the “inprinting on the wrong species” hypothesis.