| Nest boxes have increased Black-bellied Whistling Duck populations by providing safer nest sites than natural cavities or terrestrial sites. However, placing nest boxes in close proximity and in highly visible locations may facilitate conspecific brood parasitism (i.e., dump nesting), which at high rates can decrease nest success and incubation efficiency that ultimately lead to reduced recruitment. Nest boxes were placed on the Welder Wildlife Foundation near Sinton, Texas and classified according to their visibility and proximity to other boxes. Nest boxes were then monitored to determine the effects of visibility and proximity of nest sites on frequencies of brood parasitism. Black-bellied Whistling Ducks preferred isolated nesting sites, but incidence of brood parasitism at isolated nest sites occurred in all clutches. Mean clutch size, was greater (P = 0.02) in nest sites ≥100m from other nests than those <100m from other nests, suggesting that isolation was not an effective defense against brood parasitism.;Habitat and spatial variables around each nest site were measured to determine factors leading to nest site selection. Black-bellied Whistling Ducks preferred nest boxes with a larger internal volume (P < 0.01). Other variables did not appear to influence nest box selection. |
