Northern Prairie Wildlife Research Center
Leonard L. McDaniel
Valentine National Wildlife Refuge
The maximum potential level of duck nest predation by bullsnakes is masked by nest destruction by mammalian nest predators. Bullsnake nest predation was >40% where nest predator control was not carried out; >65% on a peninsula where only mammalian nest predators were controlled; and where both reptilian and mammalian nest predators were controlled and/or excluded from an island nest destruction was reduced to >5%. Mallard (Anas platyrhynchos) nest density on this island during 1982-88 increased from 0.2 to 55 nests per acre; however, blue winged teal (Anas discors) nest density only increased from 1.7 to 8 nests per acre.
High duck nest success and nest density were only achieved where potential nest predators were effectively removed and/or excluded from vegetative cover attractive to nesting female ducks. The bullsnake is an extra element, evidently unique to the Nebraska Sandhills, which complicates an effective and efficient duck nest predator control effort.