Turkish Journal of Zoology Turk J Zool (2016) 40: 925-932 http://journals.tubitak.gov.tr/zoology/ © TÜBİTAK Research Article doi:10.3906/zoo-1507-50 Distribution and current status of Cricetulus migratorius (Mammalia: Cricetidae) in Bulgaria, with comments on its status in the Balkans Nedko NEDYALKOV* National Museum of Natural History, Sofia, Bulgaria Received: 01.08.2015 Accepted/Published Online: 05.01.2016 Final Version: 06.12.2016 Abstract: During the last decade I collected extensive new information about the distribution of the Grey hamster (Cricetulus migratorius) in Bulgaria, mainly through the study of pellets of birds of prey and owls. New data about the dental morphology and morphometrics, distribution, and current status of the Grey hamster in Bulgaria are presented. The Grey hamster has been found in the diet of the Barn owl (Tyto alba), Little owl (Athene noctua), and Eastern imperial eagle (Aquila heliaca). It contributed a negligible part of the studied pellets: only 0.06% of individuals from 27,449 small mammals. The presence of the species was confirmed only in south- eastern Bulgaria, while in northern Bulgaria the species went extinct. The species’ distribution in the Balkans is discussed. Key words: Grey hamster, morphology, birds of prey, owls, distribution 1. Introduction In Bulgaria the Grey hamster was first discovered The Grey hamster (Cricetulus migratorius Pallas, 1773) in 1959 (Peshev et al., 1960). Only single findings were is distributed from the Balkans to China and Mongolia reported afterwards, mainly from south-eastern Bulgaria, (Kryštufek et al., 2008). It can utilise various habitats reported in regional journals (in Bulgarian: Straka, 1962; – steppes, semideserts, and even the surroundings of Markov, 1964; Simeonov, 1964a, 1964b). Here I summarise human settlements – and can go up to 4300 m above sea the distribution and the species’ status in Bulgaria, and level (Gromov and Erbajeva, 1995). This is one of the present new data about the species’ morphology from the three hamster species that occur in Europe (Mitchell- western part of its range. Jones et al., 1999). For all of them significant changes and decreases in their ranges have been observed, mainly due 2. Materials and methods to agroenvironmental practices (e.g., changes in habitat This research is based on collected material from pellets utilisation, use of pesticides) or collection for the pelt and food remains from different birds of prey and owls (Cricetus cricetus) (Nechay, 2000). that I obtained between 2001 and 2014 from various parts During the Pleistocene, the Grey hamster was of Bulgaria. I identified and analysed a total of 27,449 widespread throughout Europe and reached Spain and individual small mammals found at roosts and nests Great Britain [sensu Kowalski (2001); the author joined from eastern and south-eastern Bulgaria of the following under this name besides Cricetulus migratorius a small species: Barn owl (Tyto alba), 20,157 small mammals; fossil form Allocricetulus bursae, but see Hír (1993) and Tawny owl (Strix aluco), 472; Little owl (Athene noctua), Cuenca-Bescós (2003) for further comments about the 1861; Long-eared owl (Asio otus), 2709; Long-legged status of these forms]. In the beginning of the Holocene buzzard (Buteo rufinus), 643; and Eastern imperial eagle the species still inhabited Slovenia (Toškan and Kryštufek, (Aquila heliaca), 1607. Some preliminary data about new 2009). In spite of its extensive range, data about its findings of C. migratorius in Bulgaria have already been morphology and variation are scarce (Pradel, 1981; presented (Nedyalkov, 2013). Doğramacı, 1989; Hír, 1993).The cricetids are amongst For morphological comparison I used 6 complete the most poorly studied rodents in the Palaearctic; thus, specimens of the Grey hamster collected from Central studying their morphology and the variation of the species Kazakhstan (46°23′30″N, 74°01′44″E) and 8 mandibles will provide key information about the group’s evolution found in the diet of Barn owl and Long-legged buzzard and its origin. from Central Anatolia, Turkey (37°19′14″N, 33°11′13″E). * Correspondence: [email protected] 925 NEDYALKOV / Turk J Zool The measurements of teeth are made in accordance birds’ diet: 0.06% of the analysed material (27,449 small with the methodology described by Pradel (1981), while mammals). the terminology used follows Hír (1989). The teeth The Grey hamsters were identified mainly by their measurements were taken by stereomicroscope (accuracy: cranial and mandibular bones. The most complete remains 0.05 mm), and molar row – coronal length, with а digital were found in the remains of the Barn owl (Figure 1). One caliper (accuracy 0.01 mm). The abbreviations of the of the strongest bones, the mandible, remained entirely characteristics are as follows: M/m – upper and lower complete in the Barn owl pellets, in contrast to those from molar, L – greatest length, W – greatest width, MNI the Little owl and the Eastern imperial eagle, where it is – minimum number of individuals, identified by the fragmented in different degrees: broken proc. coronoideus, maximum count identified fragments from the left and proc. articularis, and proc. angularis (Figure 1). This is due right mandibula, the maxilla, or separate teeth. to differences in the feeding biology and habits of these species: the Barn owl swallows its prey (small mammals) 3. Results whole, while birds of prey (eagles, buzzards, falcons) 3.1. Data from the diet of the avian predators tear their prey to pieces (even small mammals) prior to From the analysed 27,449 individual small mammals from swallowing, as do some small owl species (such as Little pellets and prey remains, a minimum of 17 specimens of owl and Scops owl) for which insects are the main food the Grey hamster were found as part of the diet of three (Marti et al., 2007). avian species: Barn owl (Tyto alba), Little owl (Athene 3.2. Morphological description data of the teeth noctua), and Eastern imperial eagle (Aquila heliaca). It was Data from the dental measurements of the Grey hamster not found in the diets of the other 3 studied species. are presented in Table 2. The Grey hamster was represented in different М1. The anterocone is usually deeply split into two proportions in the diets of the avian predators (Table cusps. The anterior connection between the paracone and 1). Altogether, it constitutes a negligible part from the protocone is present or poorly developed, but sometimes Table 1. Cricetulus migratorius localities and proportion in the diet of the owls and the Eastern imperial eagle. Predator Location Collection day C. migratorius (MNI) All small mammals Tyto alba Matochina 20.8.2008 1 50 Tyto alba Levka 03.5.2006 14 532 Athene noctua Raykova mogila 10.8.2012 1 11 Aquila heliaca Sliven 15.3.2008 1 7 Figure 1. Degree of fragmentation of Cricetulus migratorius mandibles found in the diets of different avian predators; from left to right: A. heliaca, A. noctua, and T. alba. 926 NEDYALKOV / Turk J Zool Table 2. Dental measurement (in mm) of Cricetulus migratorius from Bulgaria. Meas. N Mean Min Max SD LM1 31 1.58 1.4 1.7 0.071 WM1 31 1.07 0.95 1.2 0.055 LM2 29 1.18 1 1.3 0.091 WM2 29 0.96 0.85 1.05 0.051 LM3 27 0.93 0.85 1 0.054 WM3 27 0.90 0.8 1 0.055 LM1-3 27 3.70 3.55 3.91 0.104 Lm1 24 1.53 1.4 1.65 0.072 Wm1 24 1.01 0.9 1.1 0.040 Lm2 25 1.25 1.1 1.35 0.048 Wm2 25 1.04 1 1.1 0.031 Lm3 22 1.07 1 1.2 0.047 Wm3 22 0.98 0.85 1.05 0.057 m1-3 20 3.85 3.45 4.02 0.140 it may be absent between the paracone. Usually there is Stara Planina Mountain (the main mountain ridge that a parastyle (morphotype C in Hír, 1993), but sometimes separates the country into north and south) (Straka, 1962). with preanterocone cingulum (morphotype A), or both of The species’ distribution is presented in two periods. them may be absent (morphotype D). These morphotypes The first one covers the time from the first finding of were observed in the following frequencies: morphotype the species in Bulgaria until 1985, when all information A, 20%; morphotype C, 40%; and morphotype D, 40% about the species’ distribution was summarised in the first (n = 20 teeth). Only an anterostyle was not observed edition of Red Data Book of Bulgaria (Christov, 1985). (morphotype B). The teeth are four-rooted. Between 1964 and 2003 there was no record of the M2. Anterior cingulum is well developed, especially on species in Bulgaria, but this was due to a lack of systematic the labial side. Mesolophe is absent. Four-rooted tooth. research in the south-eastern part of Bulgaria. Data about M3. The protocone is well developed; hypocone the species’ distribution after 2003 come from the study and metacone are strongly reduced. The anterolingual of diets of different owl species (Georgiev, 2004; Milchev, cingulum is less pronounced or may be absent. 2009). m1. The anteroconide is divided by a depression into My research confirmed the presence of the species in a lingual cusp and a labial cusp, which are of similar size. two old locations, around Sliven town (Simeonov, 1964a, Preanteroconide cingulum is absent. 1964b) and Levka village (Peshev et al., 1960); and one m2. All the four primary cusps are well developed. The more recent location, Rajkova mogila village (Georgiev, mesolophid is also absent in this element. 2004). m3. Mesolophid may or may not be present.