抄録
The Oriental Skylark Alauda gulgula is a widespread species, but its natural history is poorly understood, especially at high altitudes. In this study, we collected breeding information on Oriental Skylarks at an altitude of 3,400 m on the northeastern part of the Tibetan Plateau and examined the effects of nest-site characteristics on nest success. The birds arrived in the study area in April, built nests in tufts of tall grass on the ground and laid their eggs (gray with brown speckles) between May and July. Clutch size averaged 3.3 eggs. Incubation was mainly by the female and lasted 12.4 days. The young left the nest when 9.7 days old. During the breeding season, individual skylarks made 2-3 breeding attempts. Nesting success, as measured by the proportion of nests from which at least one young fledged, was 41.3%. Predation accounted for the majority of failed nests. Some predators (e.g. carnivores) took both skylarks and Mountain Pikas Ochotona curzoniae, although the pikas, as the dominant mammals of the region were the key resource for their common predators. GLMM results show that the density of pika burrows around Oriental Skylark nests significantly influenced nesting success, while other potential variables were not statistically significant. Pika burrow density around successful nests was significantly lower than that around failed nests implying that an indirect effect of the presence of sympatric prey species with shared predators greatly influenced the nesting success of sympatric birds. Avoiding spatial interactions with coexisting key prey species of locally common predators is a successful strategy for improving nesting success.
