First-year survival probability of migratory passerines during the period between fledging and first reproduction is a highly variable parameter that has a major effect on population dynamics. We used a long-term mark–recapture dataset (2002–2018) to examine first-year survival of 3 passerine species breeding in abandoned agricultural fields of northwestern Russia: Booted Warbler (Iduna caligata), Whinchat (Saxicola rubetra), and Western Yellow Wagtail (Motacilla flava). We banded 3,457 nestlings, including 1,363 Booted Warblers, 1,699 Whinchats, and 395 Western Yellow Wagtails, and resighted 12 Booted Warblers, 29 Whinchats, and 13 Western Yellow Wagtails in the year after fledging. We evaluated first-year apparent survival rates using Cormack-Jolly-Seber models in MARK program within the multispecies approach. We tested effect of fledge date on the first-year apparent survival. In all focal species, first-year apparent survival rates were low and reached the lower limits known for migratory passerines. We found no differences in first-year survival rates among the 3 species: the estimated average first-year apparent survival rate of all species was 0.05 ± 0.01. The fledge date had a considerable impact on first-year survival rate: later fledge dates negatively affected first-year survival. We suggest that first-year apparent survival rates in our study were low due to low natal philopatry and high mortality in the post-fledging period. Low apparent first-year survival may be a specific feature of open-nesting birds breeding in abandoned fields that are low-quality habitats because of high predation pressure.

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The article discusses data on paleosol, mineralogy, and paleobotany obtained as a result of studying material collected from the Maastricht-Early Paleocene sediments of the Tanyurer Formation of South Chukotka. The burial of organic matter in the sedimentary rock of the Tanyurer Formation is associated with deflationary processes during the period of activation of volcanic activity. On the drained volcanic plateau of soil formation, a sod humus-accumulative process prevailed under the steppe vegetation. Humic substance dispersed in sedimentary rock was represented by a group of humins resistant to microbial decomposition. As a result of exposure to high pressures and temperatures, the colloidal form of humus was transformed into kerogen. Organic compounds (cellulose, lignin) in the plant tissue of buried tree trunks were replaced by silicon compounds. Weathering processes have affected the thin surface layer of dense sedimentary rock. Under the influence of the temperature and humidity gradient, loosening of loose rock and disintegration of clots of colloidal forms of humus occurred.