Black-bellied whistling duckling

Peace River Wildlife Center was the scene of an alien invasion recently.  Not of the extraterrestrial variety, but the illegal alien type.  Just as our astute political pundits have prophesized, some of our south-of-the-border neighbors are rushing our boundaries to avail themselves of our wonderfully inclusive health care system.

A black-bellied whistling duck chick was admitted to PRWC last week.  While it can be difficult to definitively identify most duck species when they are tiny chicks (they all look pretty much the same) the whistling duck is quite distinctive.  With an almost checkerboard pattern of yellow and black down, its appearance is like no other duckling.

Of the eight species of whistling ducks in the world, only two—the black-bellied and fulvous whistling ducks—occur in the United States.  With their long legs, long neck and short tail, they resemble geese or swans and are actually more closely related to those species than to other ducks.  Both the black-bellied and fulvous are found primarily in Mexico and Latin America, but have been making in-roads over the last 30 years to becoming more common year-round residents in south Florida.  While the fulvous is also seen in Asia and Africa, the black-bellied is solely a New World species.

The adult black-bellied whistling duck has some other unique physical features.  Sexually monomorphic (both males and females look the same), it has a red bill, pink feet, white wing-patches, and a black belly. The head is brownish-gray with a white eye-ring.  Highly gregarious, it can be found in large flocks, up to 1,000 birds, at the edges of shallow ponds, golf courses, city parks, and schoolyards.  A nocturnal feeder, it eats primarily plant materials and rarely insects or mollusks.

Whistling ducks were previously classified as tree ducks, but further study proved that most of the subspecies do not nest in trees.  The black-bellied whistling duck, however, actually does prefer to nest in natural cavities in trees.  It will use a nest box if provided and even lay eggs on the ground in rare circumstances. 

The black-bellied also has a propensity for intraspecific brood parasitism or dump-nesting.  These respectively scientific and hillbilly-sounding terms refer to the fact that the black-bellied female will lay her eggs in a nest belonging to another black-bellied pair.  While it is difficult to ascertain whether an egg came from the specific female to whom the nest belongs, the single average clutch size is 14 eggs.  Nests containing over 100 eggs have been studied, although most brood parasitized nests contain an average of 24 eggs.  These numbers make it obvious that a single bird has not laid all of the eggs.

The male usually accompanies the female to the nest for egg laying.  Interestingly, the pair will visit more nest sites than are used for laying, possibly to confuse predators or discourage brood parasitism.  The eggs incubate for approximately one month, during which time both parents take an active role in sitting on the eggs and defending the nest.  Both male and female will engage in broken-wing displays to distract predators if flushed from the nest.  The young are able to fly by two months of age.  They remain with the adults for an additional four months after fledging.  As a neotropical species, they are able to begin breeding in the first year of their lives without harsh weather constraints to delay them.

Luckily for us, this adorable little alien was able to find his way to get the help he needed.  Having gotten separated from his parents and siblings, he will be raised at PRWC until he is ready for release back to the vicinity of his family.  Until the great wall goes up to discourage this rampant disregard for territorial boundaries, PRWC will continue to treat the vast variety of species we see, including migratory ones.  And if we are waiting for the birds themselves to be able to afford to build the wall, this could go on for the unforeseeable future.

by- Robin Jenkins, DVM

Black-bellied whistling duckling in Callie's hands
Black-bellied whistling duckling in Callie’s hands