Место издания:Ornithological Society of Japan Tokyo, Japan
Первая страница:87
Последняя страница:87
Аннотация:Nest survival in Arctic-breeding shorebirds was studied on south-eastern Taimyr (72°51' N, 106°04' E) in 2011 and 2012 by monitoring the fate of clutches in the nests of the pectoral sandpiper (Calidris melanotos) [PSN]. To evaluate the role of nest site selection we deployed quail eggs in artificial nests in random points [ANR] and in the nests used by pectoral sandpipers in the previous year [ANS]. Abundance of alternative prey (lemmings), activity of predators, nesting habitat and overhead concealment of nests were considered factors potentially important for nest survival. Automatic cameras were installed at the nests of all types to aid predator identification. Lemming abundance was low in 2011 and extremely low in 2012; avian predators nested in low numbers both in 2011 and 2012. In 2012, Arctic foxes were much more active than in 2011 (0.58 encounters per 24 h in 2011 and 2.54 in 2012), and were the only predators recorded by cameras in 2012. Daily survival rates (DSR ± SE) differed significantly between 2011 and 2012 and were, respectively, 0.885 ± 0.020 and 0.606 ± 0.051 for PSN, 0.845 ± 0.027 and 0.0 for ANS, and 0.789 ± 0.035 and 0.0 for ANR. DSR of PSN did not differ significantly from that of ANS, but was higher than in ANR, which tallied with differences in concealment between these categories of nests. At extremely low abundance of alternative prey, Arctic fox remained the only confirmed and very efficient predator of shorebird clutches, while at the higher lemming abundance avian predators could have contributed to shorebird clutch predation, as indicated by differences in survival of clutches with different concealment. Experiments with artificial nests is a useful tool for interpreting impacts of certain factors on nest survival, but cannot be used to obtain an unbiased measure of bird nest survival.