New records of Suncus etruscus (Soricidae, Mammalia) and its current status in Bulgaria

We present 17 new records of Suncus etruscus in Bulgaria, and the first finding of the species north of Stara Planina Mountains. The species is recorded in the diet of three owl species - Tyto alba, Asio otus and Athene noctua, and one bird of prey - Aquila heliaca. The bulk of records originated from T. alba, in the rest raptor species it is taken randomly and consists negligible part of their diet. Additionally, five dead shrews were used, which provided hard evidence for the presence of S. etruscus in north Bulgaria. All data on the species distribution in Bulgaria are summarised and the roads for its invasion are discussed. Climate change is considered as an expansion trigger for spreading of the Etruscan shrew

Species composition and conservation of small mammals (Mammalia: Erinaceomorpha, Soricomorpha, Lagomorpha, Rodentia) in Vrachanska Planina Mountains

A review on the composition of the small mammals in Vrachanska Planina Mts. was completed using published and author’s data. A total of 27 species occur within the territory. All of the species found are typical for the region. The species with the highest conservation status, the European ground squirrel Spermophilus citellus, disappeared from the region in the early 1950s. In the last years activities on its recovery were carried out. We analyze the threats for the small mammals and propose conservation activities to improve their conservation status

Distribution and taxonomy of the Grey voles (Mammalia, Rodentia, subgenus Microtus) in Bulgaria

Grey voles (subgenus Microtus), widespread in Eurasia, may be important pests and could cause serious damage to agricultural grain fields. In Bulgaria two morphologically similar species are present (Microtus arvalis Pallas, 1778 and M. rossiaemeridionalis Ognev 1924), which are impossible to identify in the field. Despite their importance as pests, very little is known about their current status and distribution. Here we cotributed new data - based on karyological examination of 27 individuals of voles. We summarized all available information on the distribution of the voles – 20 published and 11 unpublished locations. Both species co-occurred together in north Bulgaria; in Thrace and the SE only M. rossiaemeridionalis is distributed. Microtus rossiaemeridionalis seems to occupy lower elevations, while in the mountain areas (above 1000 m) only M. arvalis is found, which corresponds well with the data from neighboring countries. The taxonomy of both species in Bulgaria is discussed

Status and distribution of dormice (Mammalia, Gliridae) in Bulgaria

Here we summarize all available data about dormice (Gliridae) in Bulgaria, published one and our own observations, collected in the last 20 years. Four species are found in Bulgaria - the Forest Dormouse (Dryomys nitedula), the Edible Dormouse (Glis glis), the Hazel Dormouse (Muscardinus avellanarius) and the Roach’s Mouse-tailed Dormouse (Myomimus roachi). Altogether we collected 1200 records from 283 locations. A database has been created in which every single record is kept. The most common and widespread species are the Edible (G. glis) and Forest Dormouse (D. nitedula), found in 212 and 139 locations respectively. They inhabit mainly the deciduous and mixed forest in the country. The Hazel Dormouse (M. avellanarius) is found in 77 locations, the bulk of them are in the mountains, but there are some locations along the Danube and southeast Bulgaria. It prefers woods with a well-developed understorey. The Roach’s mouse-tailed dormouse (M. roachi) is the rarest one - found in 26 locations in southeast Bulgaria. In contrast to the other dormice, it avoids woods and lives in semi-open habitats with shrubs, tree lines, and islands in grasslands and agricultural fields. There are several anecdotal reports of the Garden Dormouse (Eliomys quercinus) but no hard proof exists for the presence of this species. We discussed the patterns of distribution, conservation status, and coexistence of Bulgarian dormice

Diet of Saker Falcon (Falco cherrug) and Eastern Imperial Eagle (Aquila heliaca) from Central Kazakhstan

Abstract. We present results from a study on the diet of Saker falcon (n = 15 nests) and Eastern imperial eagle (n = 2 nests) from south Kazakhstan, on the basis of food remains and pellets collected during the 2009 breeding season. The main prey for Saker falcon was predominantly rodents living in middle-size colonies -Spermophilus erytrogenys and Rhombomys opimus. We also present the results from the diet of two pairs of Eastern imperial eagles nesting close to Balkhash Lake

Ecology and biology of the Roach’s Mouse-tailed Dormouse (Myomimus roachi, Bate 1937)

The Roach’s Mouse-tailed Dormouse (Myomimus roachi, Bate 1937) is endemic to the Western Palearctic (occurring in SE Bulgaria, Turkish and Greek Thrace, and western Anatolia) and is one of the less known mammals within the region. There is no information about its biology and ecology in the wild. In the course of the past 3 years (2019-2021), we conducted intensive research on a small population situated in southeast Bulgaria (Sakar mountain). The population was regularly monitored during the active time of the species. To study its ecology and biology we used a combination of nest boxes, live traps and camera traps. During this period, we collected 259 records of sex, age, and weight. Those bigger than 10 g. were microchipped. The active period for the Roach’s Mouse-tailed Dormouse lasts between April and September. Males emerged first from hibernation at the end of April (24th of April - the earliest registration). During this short active period, the dormouse breeds only once, the litter size being between 5-9 young. The first young appeared at the end of June. We observed a summer dormancy (estivation); the adult males became less active and went in the estivation first. The last active dormice were observed in the first ten days of September.Here we also present data about the population numbers and dynamics, age, and sex structure of Roach’s Mouse-tailed Dormouse in the study area

Does Temporal and Spatial Diet Alteration Lead to Successful Adaptation of the Eastern Imperial Eagle, a Top Predator?

Predator–prey interactions may be linked to different temporal or spatial patterns, including dynamics in prey populations. Therefore, understanding the adaptive capacity and how top predators respond to shifts in prey abundance and availability is crucial for their conservation. In this study, we investigated the diet pattern of the endangered Eastern Imperial Eagle facing long-term and large-scale changes. We studied the abundance variation of its profitable prey, sousliks, and how it reflected on eagle population trajectories in a regional and temporal context. We found a significant diet alteration expressed in large decrease of brown hare (β2 = −0.83), poultry (β2 = −0.81), gulls (β2 = −0.71), and water birds (β2 = −0.57), and an obvious increase of northern white-breasted hedgehog (β2 = 0.61) and doves (β2 = 0.60). Raptors and owls raised their participation (β2 = 0.44), but white stork and different reptiles supplied more biomass. Abundance of European souslik decreased through the studied periods (adjusted R2 = 0.25, p < 0.001) which accounted for the lower proportion of this prey in the eagle’s diet. Nevertheless, the eagle population successfully adapted and significantly increased (β2 = 0.97) in most of the distribution area. The trophic strategy used by this top predator related to opportunistic foraging represents an ecological advantage that allows the species to adapt to different habitats and guarantees its future. The observed prolonged diet alteration could result in a significant negative attitude among different groups such as hunters, pigeon fanciers, and poultry keepers towards eagles. Therefore, enhanced communication with key stakeholders is needed. Conservation efforts should be focused also on the preservation of the species’ main foraging habitats and the restoration of damaged ones so as to maintain the good conditions of both primary food source and subsequent prey

The small mammals (Eulipotyphla, Rodentia, Lagomorpha) of the Sarnena Sredna gora Mts

As a result of a large-scale study on the small terrestrial mammals (Eulipotyphla, Rodentia, Lagomorpha) of the Sarnena Sredna Gora Mts., through various methodological approaches and methods, we collected data about 2460 individuals, belonging to 30 species. The established species composition represents about 70% of the small terrestrial mammals of Bulgaria, which indicates the presence of a rich faunal complex. Of the established species, 6 are protected, 2 are defined as conservationally significant, with a limited distribution for the area, 3 species are synanthropic. For the first time we confirmed the presence of Sorex araneus, S. minutus, C. glareolus in the Sarnena Sredna Gora Mts. The nutria (Myocastor coypus), the European hare (Lepus europaeus), and the Red squirrel (Sciurus vulgaris) are hunting objects, and the nutria is also included in the list of invasive alien species in Europe. For the first time, the mountain habitats of the small mammal fauna of Sarnena Sredna Gora have been studied, typified, and mapped, and the species richness, zoogeographical structure, nature conservation status, and regularities in its distribution and origin have been analyzed

Does Temporal and Spatial Diet Alteration Lead to Successful Adaptation of the Eastern Imperial Eagle, a Top Predator?

Predator–prey interactions may be linked to different temporal or spatial patterns, including dynamics in prey populations. Therefore, understanding the adaptive capacity and how top predators respond to shifts in prey abundance and availability is crucial for their conservation. In this study, we investigated the diet pattern of the endangered Eastern Imperial Eagle facing long-term and large-scale changes. We studied the abundance variation of its profitable prey, sousliks, and how it reflected on eagle population trajectories in a regional and temporal context. We found a significant diet alteration expressed in large decrease of brown hare (β2 = −0.83), poultry (β2 = −0.81), gulls (β2 = −0.71), and water birds (β2 = −0.57), and an obvious increase of northern white-breasted hedgehog (β2 = 0.61) and doves (β2 = 0.60). Raptors and owls raised their participation (β2 = 0.44), but white stork and different reptiles supplied more biomass. Abundance of European souslik decreased through the studied periods (adjusted R2 = 0.25, p 2 = 0.97) in most of the distribution area. The trophic strategy used by this top predator related to opportunistic foraging represents an ecological advantage that allows the species to adapt to different habitats and guarantees its future. The observed prolonged diet alteration could result in a significant negative attitude among different groups such as hunters, pigeon fanciers, and poultry keepers towards eagles. Therefore, enhanced communication with key stakeholders is needed. Conservation efforts should be focused also on the preservation of the species’ main foraging habitats and the restoration of damaged ones so as to maintain the good conditions of both primary food source and subsequent prey

Diet of Eastern Imperial Eagle (Aquila heliaca) in Bulgaria: composition, distribution and variation

The Eastern Imperial Eagle (EIE) is a top predator exploiting different prey in different parts of its distribution. In this study, we summarise data collected over a long period of time (for 25 consecutive years), identifying key prey species in the different regions, as well as clarifying seasonal preferences in the eagle’s diet. Most studies on the EIE food composition covering different parts of the species distribution range analyse the breeding season, while data about the winter diet are scarce. To the best of our knowledge, this is the first study detailing the differences in EIE’s dietary preferences between the breeding and the winter periods. We identified 4891 specimens belonging to 196 different taxa, which represents the most comprehensive study considering the diet diversity of this threatened species. Mammals represented the largest proportion of the diet, followed by birds and reptiles. Northern White-breasted Hedgehog was the most common prey, accounting for 25.7% of the total prey caught and 26.75% of the biomass. The European Souslik was the second most important prey with 14.35% participation in the eagle’s diet, but with a 3.75% contribution to the biomass. As we predicted, prey composition and main prey species varied spatially and seasonally. Modelling differences in the EIE diet, we found that the “territory effect” had the strongest impact on the dietary variations. Diet diversity differed significantly between regions (F = 12.6, df = 4, p = 0.01). During the breeding season, eagles fed mainly on Hedgehogs (29.88%), Sousliks (16.85%) and Storks (7.74%), while the winter diet was predominantly small rodents (44.17%) and songbirds (13.96%). We found that top predators, such as EIE, have successfully adapted to a novel food source, which is abundant in the area. The detected flexibility in the diet of the species and its ability to switch to alternative prey, if available, when the primary prey decreased, should be considered when planning species conservation efforts. Investigating the temporal change of the main prey in the eagle’s diet is also crucial for further species conservation measures