Are found in both the Mississippi and Atlantic flyways, but blacks are becoming less populous in most of their ranges. The major reasons for this population decline are; loss of habitat, and secondly, because of pressure and inter breeding with mallard populations. 

Blacks are a very wary bird, and will decoy, and even respond to calling, but if they see or hear one item out of place, they'll spook - and not even take a second look. Hunters have to be 'right-on' when hunting these birds. They are excellent table fare, and are slightly larger than mallards, but hardly noticeably. These birds will be hunted best in remote areas, but will congregate with mallards ( but usually slightly aloof from the mallards) in major staging areas. 

They too, will visit grain fields, but will more often pick very remote potholes/ponds/wetlands in their wary fashion. They won't take much shooting pressure, and concentrations of blacks, if you have them in your area, will 'pull out' and head for more remote areas after being shot at relatively few times. 

In most areas of North America, the bag limit for this superlative duck is drastically reduced, owing to it's 'crashing/declining' numbers. Black's seem reluctant to successful change, and as wetlands in it's typical range decline, so may the black duck. I hope we are able to turn this sad process down, and reverse it before it is too late. If this creature has a sad demise, hunters will likely take the brunt of the blame. Loss of habitat, and dominance for breeding range, and interbreeding by mallards are what truly decimate black's numbers - not hunting/over hunting. 

Make no mistake though - the anti-hunting faction will endeavour to get the most mileage from the MISINFORMATION that they puke out at every opportunity to unknowing persons - foolish enough to give them an ear - or more importantly - to them - DOLLARS($$$$$$$). They're ASSHOLES!