Vol 104, No 2 (2025)

The duration of the moult and its different stages in young Bramblings, their variability under the influence of photoperiodic conditions are considered. The timing and duration of moult seasons in different places of the diastributiion area are also investigated, and their determining factors clarified. The moulting process is divided into 7 stages. The signs of the stages are the beginning or end of feather replacement in the selected tracts of the feather coat. An analysis of the experimental data revealed the influence of photoperiodic conditions on the duration of the moult of an individual. Under photoperiods corresponding to early moult timing, moult duration averaged 62.0 days, vs 52.3 days under the conditions of late moult timing. The moult duration is shown to drop as a result of a decrease in the duration of the beginning stages. Data derived from repeated catches in nature confirmed the results of the experiment. A negative relationship was found between the timing of the capture of Bramblings and the duration of their intervals between stages 2 and 3, 3 and 4. A comparison of the duration and timing of the seasons of post-juvenile moult at four different places of the distribution area showed their great geographic variability. The duration of the season is increased in the following sequence: the Lower Ob region (66°40 N, 66°40 E), the White Sea region (67°06 N, 32°41 E), the Middle Ob region (59°58 N, 74°22 E), and the Ladoga region (60°41 N, 32°57 E), amounting to 39, 64, 92, 116 days, respectively. In almost the same sequence, the dates of these seasons reliably shift from early to late. The median catch dates for moulting birds are 24.08 in the Lower Ob region, 28.08 in the White Sea region, 1.09 in the Ladoga region, and 10.09 in the Middle Ob region. At the early start of the moult season in the Ladoga region (2.07), its end turned out to be one of the latest (25.10), and the duration is twice as long as that of an individual moult. In the Lower Ob, at the late start of the season (1.08), it ends earlier than at other locations of the study area (8.09), and its duration is almost half as long as the moult of an individual. An analysis of the number of birds with different stages and a comparison of the timing of registration of successive stages at each research location with the duration of interstage intervals in moulting individuals has allowed us to come to the following conclusion. During the post-juvenile moult season, the Lower Ob region is inhabited mainly by local Bramblings with the beginning moult stages. They fly away from this subarctic area before the inset of intense feather replacement. In the study area of the White Sea region, the moult season is dominated by birds that appeared as a result of post-fledging (juvenile) migration. They have middle moult stages. In the Ladoga and Middle Ob regions, both local birds and Bramblings from remote territories are recorded. Among the latter, there are birds that live during middle moult stages, but individuals with the last moult stages, which follow in transit during the autumn passage, predominate. This determines the longer duration and the later dates of the moult seasons in the Ladoga and Middle Ob regions.

A study of a wild boar population’s vigilance was carried out 50–80 years following the creation of the Sikhote-Alin Nature Reserve, Russian Far East and the cease of hunting. The defensive behavior of the wild boar depends especially strongly on the tiger (Panthera tigris tigris) and the brown bear (Ursus arctos). Based on 298 encounters, the following responses were determined: (a) reactions of wild boars to stimuli associated with danger, (b) parameters of alertness (3.2 hours of measured time, frequency of observed postures and movements). Response features to different signals were also determined using snow-tracking. Nonparametric and, after normalization, parametric criteria were applied. Vigilance towards humans is maintained due to a generalized reaction to real danger (large predators) and probably because the wild boar population of the nature reserve is not isolated from the surrounding areas. In more than 70% encounters, wild boars detected danger by sounds accompanying movements (from almost 0.6– 0.8 km). Visual scanning of movements and the identification by smell are important in detecting the close presence of a predator, which is essential in the tiger’s usual hunting methods. The reaction to the smell of human or tiger tracks intensified during the periods of frequent visits by the predator to the wild boar’s habitat, as well as after its long absence, depended on the meeting place. The vigilance decreased during the periods of famine. Wild boars showed the ability to quickly extrapolate the direction of the movement of a dangerous object. Guards and boars over 2 years old in maternal groups were seen in 35.7% cases; in 16% cases, there was no obvious guard; in 48.3% the situation was not determined (for small groups in 89.9%). Wild boar guards in a calm situation spent an average of 8–9% of their time on vigilance when resting and 11–12% when grazing. Vigilance rates increased 16.2–41.3 times in different individuals and at different times in the same wild boars with the risk of a predator encounter or extraneous sounds. Only a small percentage (≤ 2%) of other individuals, with alternating vigilance in groups, complemented the groups’ general vigilance. Individual differences in vigilance at different times in the same wild boars were determined. Small average values of alertness (with frequent reactions) seem to be consistent with the hunting tactics of the tiger, which alternates pursuit of the wild boar with long cessations and hunting in other areas, as well as with the ability of the wild boar to react to an unexpected attack by a predator.

The habitat conditions and genetic structure of the native population of the common hamster in Moscow, listed in the 3rd edition of the Red Data Book of Moscow City with the status 3 (vulnerable in the city), are described. Information about the presence of the common hamster in Moscow dates back to the end of the XIX century. Over the past 50 years, the Moscow population is noted to have sharply declined in abundance and has survived only along the Yazvenka River and the banks of the Borisov ponds. These areas are separated by a distance of 6 km. The genetic differences between these subpopulations are 14.6%. The diversity of the Moscow subpopulations is reduced both in mitochondrial DNA (there are only two mtDNA haplotypes in the city (in the cytochrome b gene + control region)) and in microsatellite markers. When analyzing 10 microsatellite loci in the Moscow population, 23 alleles were found. This is two to three times lower than in the populations of the common hamster in Astana, Simferopol and Kislovodsk. Haplotypes of the Moscow population together with those of the hamsters from the Tula and Vladimir regions form a well-supported clade on the phylogenetic tree. Genetic analysis of Moscow subpopulations of the common hamster confirms the adequacy of including this species in the Red Data Book of the Moscow City.

Based on zoological collections and published information, morphological characteristics of the teeth and mandibles of Lemmus cf. sibiricus from the Eopleistocene Skorodumian faunal complex of western Siberia are compared with those of modern and fossil Lemmini from Europe and Asia so as to clarify the taxonomic identity and determine the place of the fossil form under consideration in the evolutionary history of the Palaearctic Lemmini. Comparative morphological approaches based on qualitative traits and linear measurements of cheek teeth, traditionally used for taxonomic diagnostics of representatives of the tribe, are used. according to the combination of apomorphic and plesiomorphic features, lemmings from the Skorodumian faunal complex of the Eopleistocene of western Siberia are shown to occupy a position intermediate between the more ancient L. kowalskii and the modern species Lemmus sibiricus. According to this intermediate position between the ancestral widespread form and the modern regional taxa of the genus Lemmus, the West Siberian Eopleistocene lemmings correspond to the East Siberian Lemmus sheri Abramson, 1992. The differences between L. kowalskii and the Eopleistocene forms are clearly recognizable and reflect the evolutionary changes in the cheek teeth associated with the transition of the Eopleistocene forms to a higher level of specialization in bryophagy. At the same time, the morphological similarity of the western and eastern Siberian Eopleistocene lemmings to each other is no higher than that of each of the regional forms to modern Lemmus inhabiting the same regions. Based on this, within the Eurasian range of the Eopleistocene Lemmus, differentiation comparable to the intrageneric differentiation within modern Lemmus could presumably have been observed. The combination of similarities in some features and differences in others most likely reflects mosaic morphological variations across the Eopleistocene range of one form, possibly a polytypic taxon, which by right of priority should be termed as Lemmus sheri Abramson, 1992. Taking into account the presence of regional features, it seems appropriate to consider the Eopleistocene lemmings of the Olerian Formation of eastern Siberia as L. sheri sensu stricto, and the lemmings from the Skorodumian faunal complex of western Siberia as the polytypic taxon L. sheri sensu lato.