ИСТИНА

Influence of nest concealment on nest survival was studied in 2011–2014 on south-eastern Taimyr (72°51'N, 106°04'E) by monitoring the fate of nests of the pectoral sandpiper (Calidris melanotos) [PSN], red phalarope (Phalaropus fulicarius) [RPN] and two types of artificial nests with quail eggs (in random points [ARP] and in the previous-year nests of pectoral sandpipers [ANS]). Quantitative assessment of overhead nest concealment was made by taking photos of white paper circles placed in the nests and further processing of images using ImageJ 1.48 software in accordance with original protocol. A degree of nest concealment significantly increased in the series “ARP (11,6±1,5%) – ANS (17,9±1,3%) – PSN (23,5±1,9%) – RPN (28,1±2,2%)”. Daily survival rate (DSR) of nests differed significantly between years, but was higher in wader nests than in artificial nests of both types. Analysis of the model of DSR dependence on the nest type, concealment, and interaction of these factors showed significant effect of all these factors, so DSR increased in the above-mentioned series regardless of the degree of nest concealment. Thus, overhead nest concealment is an important, particularly in years with high activity of avian predators, but not exclusive factor affecting nest survival in tundra-nesting waders.