Nest site selection of the Southern Pale Chanting Goshawk in the Little Karoo, South Africa
AbstractThis study investigated whether Southern Pale Chanting Goshawks Melierax canorus that est in the low woody vegetation of the arid Little Karoo reduce nest predation by selecting nest trees and sites that are less accessible to and conspicuous for terrestrial predators. The 114 nest trees and shrubs sampled were taller (0 = 4.4m) than surrounding random trees (0 = 3.0m). The birds selected bush clumps for nesting that contained, on average, two plants, including creepers, compared to the 1.4 plants in random clumps. The birds also nested mainly in irregular and dome-shaped trees, a selection that differed from the dominant shapes of random trees. Most nests were placed in the centre of the trees and thorns and shoots covered the main stem of 68% of nest trees. In spite of these preferences, only nest height and — to a lesser extent — nest placement and tree shape, prevented predation by visually hiding the nest. The other features had no impact on predation, indicating that once a nest was discovered, the predators were able to climb through the foliage to the nest. Pale Chanting Goshawks therefore had some success in hiding their large nests in the low and sparsely-growing arid trees and shrubs. Although 19% of nests studied were depredated, the seasonal, irregular and low-density breeding pattern of the birds probably resulted in their offspring being an unpredictable food source for opportunistic predators.
Ostrich 2006, 77(3&4): 119–126