For half a century the continental black duck population has been declining. In the western parts of its range, the once relatively abundant black no longer exists. Three factors have undoubtedly played a role in this decline: (1) the loss or degradation of breeding, staging and wintering habitat, (2) hunting, and (3) the hybridization and competition with mallards. Nobody knows the relative importance of these factors, but it is clear that each could have a significant impact on black duck populations. What waterfowl hunters across much of the species’ range can tell you for certain is that today they have little opportunity to hunt this wary, exciting duck, a bird many Atlantic gunners rate as the most challenging.

The historic decline of the black duck can be seen in the following graph.

ATLANTIC FLYWAY BLACK DUCKS

1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

Year

Figure 1. Winter surveys reveal the population of black ducks along the Atlantic Flyway has fallen from 582,453 in 1955 to 184,055 in 2005, a decline of 68 percent. Source: USFWS.

Many biologists believe it is only a matter of time before mallards displace black ducks everywhere on the continent. In the 1960s some predicted black ducks would be rare by the new millennium. But a new analysis of Christmas Bird counts – the annual census of birds across North America – suggests the continental population is stable, but its distribution has shifted toward the Northeast. Blacks may still be declining in parts of its range, or gone from locations where they were once common, but this is not true in the forested and coastal habitats of the Northeast.

This raises a question: Why has the mallard apparently been unable to make inroads into these habitats?

Black duck habitat in the Northeast has not changed significantly, unlike wetlands in other parts of the black duck’s range. This is important because of the advent of milder winters. This has resulted in increasing numbers of black ducks remaining farther north, allowing them to avoid both increased human activity and degraded wetlands.

Hunting pressure in the sparsely populated northeast also is significantly lower than farther south along the Atlantic Flyway, still a stronghold of the black.

Observations also reveal that although mallards have been in Atlantic Canada for several decades, they are not significantly increasing, nor are they expanding into the forested and coastal habitats of the more northerly parts of the region.

It is important to note black ducks are primarily a coastal duck adapted to brackish water habitats, and only secondarily moved into freshwater habitats as far west as the Mississippi River. Blacks have evolved unique adaptations to coastal habitats that are not found in the predominantly freshwater mallard.

The landscapes of the northeast have much less food than the prairies where mallards primarily evolved. In the Northeast, mallards typically nest on agricultural lands, but agriculture is sparse as one goes northeast and soon becomes non-existent. Black ducks on the other hand nest in a wide range of natural habitats and avoid agricultural land because of human activity. They are not avoiding highly competitive mallards in these areas, as many have argued on the basis of casual observation; they’re avoiding people. Blacks are continuing to use the natural landscape as they always have.

In Nova Scotia, for example, many black ducks take advantage of special physiological and behavioral adaptations to raise their ducklings in brackish water estuaries. Mallards raise their broods in freshwater. Black ducks have special salt glands that allow them to drink salt water and convert it to fresh. These glands are poorly developed in mallards. In addition, black duck females take their broods to parts of estuaries where they can find freshwater. Estuaries are food-rich natural habitats where female black ducks can successfully raise their young. Having exclusive access to this habitat gives blacks a competitive advantage over mallards.

All of this suggests the black duck has found a refuge in the Northeast where it can avoid mallards. Add to this the fact that habitat conditions are likely to remain stable for decades to come. Moreover, hunting pressure is likely to remain light. Thus, there is reason to believe that blacks may continue to thrive in traditional landscapes of the Northeast.

If this analysis is correct, then the future of the black buck is more positive than many have predicted.