Seasonal population dynamics of the common redstart, Phoenicurus phoenicurus (L.), in mountain Crimea: Contributions of local and migrating populations

Abstract

Common Redstarts live in the Crimea mainly in the mountain part of the peninsula, which is occupied by birds of the Iranian subspecies, P. phoenicurus samamisicus. During seasonal migrations, migrating Common Redstarts of the nominotypical subspecies, P. phoenicurus phoenicurus, appear in the Crimea, and birds of both subspecies can occur together in the Mountain Crimea. The purpose of this study was to analyze the influ� ence of seasonal migration of Common Redstarts, nesting cycle phases, and other biological factors on the seasonal population dynamics of this species and estimate the contribution of local populations and those migrating via the peninsula to seasonal changes in its abundance. Studies on the biology of Common Redstarts, cen� sus trapping, and morphological analysis of trapped birds were performed in different areas of the Moun� tain Crimea, including the northern foothills and the southern Crimean coast, in 1989–2011. The results of observations in the steppe part of the peninsula were also included in analysis. Specimens of Common Redstarts from the Crimea were examined in collec� tions kept in the National Museum of Natural History, National Academy of Sciences of Ukraine, and the Zoological Museum of Taras Shevchenko National University (Kiev). Published data from the catalogue of the ornithological collection in the Museum of Nature, Kharkov National University (Devyatko and Dzhamirzoev, 2008), were also taken into account. Male Common Redstarts were identified to subspecies in the course of analysis of museum specimens, exam� ination of trapped birds, and visual observations with optical devices or, at small distances, with naked eye: males of the subspecies P. p. samamisicus have a char� acteristic white spot on the wing, which is absent in males of the nominotypical subspecies. Most males can be reliably identified to subspecies by this crite� rion. It is only in rare cases that local birds have this spot so strongly reduced that it cannot be detected in the field. The main data on population dynamics were obtained in the mountain forest part of the Crimean Nature Reserve, in the central area of the Crimean Mountains, in 1989–1995 and 2009. The abundance of the birds was determined by the standard procedure (Ravkin, 1967) along permanent 2�km routes with an unlimited census zone width (the actual distance to Redstarts recorded during censuses was at most 50 m). The routes were laid so as to pass through various biotopes, with reference to the classification of bird habitats of the Crimean Nature Reserve (Kostin and