Lia and Ron previously supplied the correct ID. However, the species is actually not all that uncommon in southwestern Arkansas (especially along the Red River) where I've encountered flocks totaling around 200 individuals. And, while it is generally uncommon elsewhere in the state, it is popping up with increasing frequency in all sections.
Discussion
4 repliesLight was poor and distance about 200 yards, so quality is minimal.
It is a Black-bellied Whistling Duck, a bit uncommon for Arkansas