A three-year experimental study with artificial ground nests was carried out in a highly fragmented agricultural landscape in Southern Bohemia, Czech Republic, to examine whether population density or spatial distribution of active black-billed magpie (Pica pica) nests contributes to the pattern of predation on dummy nests. Out of the total of 335 dummy nests with a known fate, predators robbed 126 (37.6%). The population density of magpies did not affect nest predation significantly, while nests placed closer to active magpie nests were predated significantly more than distant nests in two out of the three years under study. Moreover, the distance to the nearest active magpie nest was found to be the most obvious factor affecting nest predation risk, among such factors as site, individual nest position, habitat type, distance to the nearest forest fragment, habitat diversity, nest concealment, distance to the nearest line habitat, and distance to a perch for avian predators. The study suggests that the spatial pattern of a dominant generalist predator can be a factor explaining the predation pattern on experimentally treated nests.