Sicista trizona
Creators: name: Don E. Wilson
name: Russell A. Mittermeier
name: Thomas E. Lacher, Jr
Publisher: name: Lynx Edicions
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Rodentia
Dipodidae
Sicista
Sicista trizona

description: 13.
Hungarian Birch Mouse
Sicista trizona
French: Siciste de Hongrie / German: Ungarn-Steppenbirkenmaus / Spanish: Raton listado de Hungria
Other common names: Transylvanian Birch Mouse (transylvanica)
Taxonomy. Mus trizonus Frivaldszky, 1865,
Felsö- Besnyö, Pest County, central Hungary.
Steppe Species Group. S. J. Petényi collected the first recorded specimens of this taxon in Tiszafoldvar, eastern Hungary, in 1843 but did not assign a name to this sample or describe specimens before his death in 1855. I. Frivaldszky in 1865 named a new taxon Mus trizonus, based on Petényi’s specimens, that he designated ajunior synonym of Mus (Sicista) vagus described by P. S. Pallas in 1779 based on material from lower Ural River. In 1882, C. Chyzer published Petényl’s manuscript notes posthumously and included a detailed description of Mus trizonus. The earlier description by Frivaldszky and the 1882 description were based on the same syntypic sample of five individuals, and according to the International Code of Zoological Nomenclature, Frivaldszky’s 1865 publication stands as the valid description of this taxon. Phylogenetic relationships of S. trizona and affinities with the other subtilis forms had not been studied since L. Méhely’s work in 1913 until T. Cserkész and colleagues in 2016 proposed elevation of trizona to species rank as a result of an integrative systematic revision based on morphological and molecular markers. Moreover, significant genetic distance between Hungarian and Romanian populations of S. trizona led Cserkész and colleagues to describe the Romanian population as a new subspecies,transylvanica. Sicista trizona is closely related to S. loriger, and together they form the western clade of the Steppe Species Group. According to the latest phylogenetic analytic results, western clade is highly divergent from eastern clade that includes S. subtilis. Subspecies transylvanica occurs in Transylvania on the Somes Plateau, Romania, near the city of Cluj-Napoca, and was only recently discovered at two localities within that region by Cserkész and colleagues in 2014. Distribution of the Transylvanian population has not yet been definitively established, but it could be more widespread than the Hungarian population; even so, transylvanica may be fragmented into isolated subpopulations, possibly inhabiting places far from currently recorded localities. Additional research is needed to classify the Polish population of S. subtilis, which is morphometrically close to S. trizona, as documented by Cserkész and colleagues in 2009. Cranial and external measurements of S. trizonaare significantly smaller than those of S. loriger. Discriminant function analysis using cranial traits clearly separates S. trizona from other subtilis forms without overlap, as shown by Cserkész and colleagues in 2009. Differences in male reproductive anatomy have been described;e.g. length and width of penile spike differ significantly in S. trizona compared with populations of S. subtilis. In S. trizona, conical penile spike is short (up to I mm) and wide (greater than 0-3 mm), but penile spikes in populations of S. subtilis and S. s. severtzovi are long (greater than 1 mm), thin (up to 0-3 mm), and dagger-shaped, as illustrated by S. I. Ognev in 1948. Single penile spike of S. lorigeris also thin and long (length greater than 2 mm), according to D. Auslinder and S. Hellwing in 1957 and Cserkész and colleagues in 2016. Shape of S. trizona baculum is markedly different from those of S. subtilis including S. s. severtzovi: on the upper one-third of the shaft, there is a wide cartilaginous border on both sides, giving a lance-head shape to the baculum. In dorsal view,its wide base and narrow slightly rounded unnotched apex are rounded. This wide base in S. subtilis and S. s. severtzovi is slightly emarginated, and tip has shallow medial notch. Karyotype of S. trizona (2n = 26; FNa = 48) is identical to that of S. loriger, as reported by I. Ham and colleagues in 1983, but no detailed study is available comparing chromosomalstructure between the two species. Two subspecies recognized.
Subspecies and Distribution.
S.t.trizonaFrivaldszky,1865—NEHungary(BorsodiMezdségLandscapeProtectedArea).
S. t. transylvanica Cserkész, Rusin & Sramko, 2016 — C Romania (Somes Plateau, Transylvania).
Descriptive notes. Head-body 54-66 mm, tail 63-95 mm, hindfoot 14-16 mm; weight 3-5-14-5 g. The Hungarian Birch Mouse is the smallest species of Sicista in bodysize. It has relatively long, semi-prehensile tail but lacks special elongation oflegs or feet. Upper parts are pale or dark brown to brownish yellow, and underparts are paler brown. It has sharply defined black mid-dorsal stripe that is often bordered by narrow bright stripe on each side, but presence of three stripes is not a reliable character for identification. Pelage color varies depending on season and age. Juveniles have more intense dorsal pelage, with vivid yellow hue on sides, and black stripes. In summer, adult dorsum is usually grayish brown. Condylobasal lengths are 16-7-18-2 mm, and lengths of upper tooth rows are 2:6-3-1 mm. Diploid numberis 2n = 26. External and cranial measurements were from specimens of undefined age and gender collected in Hungary and published by Cserkész and colleagues in 2009.
Habitat. Prefered habitat includes undisturbed areas and islands of tall herbaceous vegetation that remain in pastures extensively grazed by cattle. In Hungary, most Hungarian Birch Mice were captured in patches dominated by thistle and creeping thistle (both Asteraceae). Some sites had been plowed 30-40 years ago, and cattle grids and farm buildings were still standing in some areas. Other habitats in the region include fescue (Festuca, Poaceae)saline meadows, wormwood (Artemisia, Asteraceae)fescue steppes, and abandoned crop vegetation, but Hungarian Birch Mice were less abundant in these habitats. Dense, unmowed,tall grass seems to be an important habitat component. In Romania, the “Transylvanian Birch Mouse” (S. s. transylvanica) was captured in tall herbaceous vegetation situated in or near cultivated fields or heavily grazed pastures. Ham and colleagues in 1983 trapped these birch mice in an abandoned vineyard that had transitioned to a reed grass (Calamagrostis, Poaceae) dominated sand steppe in Deliblato, Serbia.
Food and Feeding. Méhely found insects and debris of marbled white (Melanargia galathea) and high brown fritillary (Argynnis adippe) caterpillars in stomachs of Hungarian Birch Mice. Captive individuals foraged on the ground and climbed vegetation to escape. Despite its small size, the Hungarian Birch Mouse is a fierce hunter and aggressively searches for insects, especially orthopterans numbed by cool evening temperatures; it also ingests spiders and larvae that are happened upon incidentally. In the wild, foods also include leaves and fruits. Captive individuals in Hungary consumed orthopterans, apple, and sunflower seeds, and green pea and small seeds of thistle and plume thistle were their favorites. They drink often in captivity. According to observations of I. Vasarhelyi in 1929, a mouse stored food in summer to use during cooler days;it left its nest only to gather food and otherwise closed the entrance. Other studies have not found any underground food storage.
Breeding. Breeding behavior of the Hungarian Birch Mouse has only been studied once in captivity by Vasarhelyi. Gestation lasted 21 days, and four offspring were born. Underground nest was ovoid, ¢.6 cm in diameter, and lined with dry grasses, dissected plants, and “the soft tuft (pappus) of red thistle.” In Hungary, an 8cm diameter nest lined with dry grass, 10 cm under the surface was found by Cserkész and colleagues in late June 2011 and contained three juveniles.
Activity patterns. Hungarian Birch Mice are crepuscular and nocturnal, and are rarely active during daylight hours. A total of 135 individuals were captured during a monitoring project in Hungary in 2006-2016. Populations were sampled monthly in April-October. Highest capture rates occurred in May due to mating activity and in July when offspring emerged from nests. Active period lasts ¢.6-6-5 months: 12 April was the earliest day that Hungarian Birch Mice appeared in pitfall traps during relatively cold ambient temperature (3°C), and the latest catch was 24 September. Weather conditions also affect activity; after rain and during slightly cooler weather, activity and trap success increased. Most individuals were captured overnight; only 7-4% was captured during the day. In captivity, mean length of daily activity in July-September was c.4 hours and 25 minutes but fluctuated dramatically. Individuals sometimes remained in their nests for 3-4 days, and one individual stayed in its nest for a week without emerging to eat or drink. Daytime activity was detected only three times in 185 days. Daily activity usually commences after sunset and is characterized by shorter active period of 1-2 hours, followed by rest. A second, more prolonged activity period typically occurred during the second half of the night.
Movements, Home range and Social organization. Despite their small body size, Hungarian Birch Mice often occupy large areas. According to a radio-telemetry study by Cserkész, they are able to move more than 100 m/h in thick grass. They are agile climbers and sometimes move by scampering and galloping. When frightened, they can leap up to 40 cm. Because they cannot jump very high, they are easily captured with small bucket traps. They do not appear to dig burrows but live in abandoned burrows of other rodents. In places where aboveground shelters (e.g. stumps,fallen trunks of trees, and driftwood) are sufficient, they apparently do notlive underground. Social organization might occur in the wild at certain times, because considerable numbers of individuals have been found in small patches of optimal habitat. In captivity, they often exhibit aggressive behavior toward conspecifics and other small rodents, but sometimes feed peacefully together.
Status and Conservation. Not assessed on The IUCN Red List due to recent elevation to species level. According to the large number of records of Hungarian Birch Mice from Hungary before 1950 that were reviewed by E. Schmidt in 1971, they were widespread and probably common in lowlands of the Carpathian Basin. They have become extinct in 98% of their former distribution due to increased use of rodenticides, habitat disturbance, and increased reliance on mechanical activities for agricultural management. Greatest threats are limited number of populations and small distribution (maximum area of occurrence 30 km? in Hungary and 54 km? in Romania). During the 20" century, isolated populations in the western distribution became extinct. The Hungarian Birch Mouse was declared extinct in Austria, and its status is possibly the same in Slovakia and Serbia. Most known habitats occur in protected areas where proper management is only guaranteed in a small part of the entire “protected” area. The European Union Single Area Payment Scheme (SAPS) pays farmers for land that they manage or own and has stimulated restructuring of the agricultural sector toward further simplification of production. This has negatively impacted the only known Hungarian population of the Hungarian Birch Mouse, which is declining at an alarming rate. Recommended habitat managementin this area is low-intensity cattle grazing, but mechanical cutting or mowing still takes place. Intensive sheep farming is also typical and only c.0-6 km* is designated unofficially as a “ Sicista Reserve. ” The Transylvanian Birch Mouse is also threatened because ideal habitats are decreasing due to spread of intensive agriculture and continued popularity of sheep farming. Meadows covered by tall and dense herbaceous vegetation are often plowed by local farmers or overgrazed by sheep. Conserving the Hungarian Birch Mouse is one of the major tasks for Hungarian and Romanian nature conservation because it is definitely on the verge of extinction. A captive breeding program will soon be initiated in Hungary as soon as certain factors such as population size allow for removal of individuals from the natural population. The Hungarian Birch Mouse should be considered as Critically Endangered on The IUCN Red List based onits restricted distribution ofless than 100 km? and only two known locations of occurrence. The Hungarian population is estimated to have decreased by 50% or more during the last three years. Nevertheless, this classification is uncertain and could be revised when new information becomes available. Surveys are urgently needed to produce more robust population estimates in Romania. Further research to monitor key populations and clarify extent of threats from mowing and its effect on population trends is vital.
Bibliography. Auslander & Hellwing (1957), Balint & Gubanyi (2006), Bauer (1954), Cerva (1929), Chaworth-Musters (1934), Chyzer (1882), Cserkész, Aczél-Fridrich et al. (2015), Cserkész, Kitowski et al. (2009), Cserkész, Rusin & Sramkoé (2016), Csorba & Demeter (1991), Demeter & Obuch (2004), Frivaldszky (1865), Ham et al. (1983), Méhely (1913), Ognev (1948), Pallas (1779), Pucek (1982, 1999), Schmidt (1971), Spitzenberger & Bauer (2001), Tvrtkovi€ & Dzuki€ (1974), Vaséarhelyi (1929).
description: Published as part of Don E. Wilson, Russell A. Mittermeier & Thomas E. Lacher, Jr, 2017, Sminthidae, pp. 9-48 in Handbook of the Mammals of the World – Volume 7 Rodents II, Barcelona :Lynx Edicions on pages 46-47, DOI: 10.5281/zenodo.6603557