Part 6: Small Carnivores and Insectivores

Northern White-breasted Hedgehog

As one might expect from such a large and diverse country, Ukraine is home to a wide range of small and medium sized insectivores and carnivores. These pursue insects, small rodents, various lagomorphs and in some cases fish and amphibians depending on the habitat. Many are similar to those we would find in Britain and northern Europe, others are unique to the region. 

To begin with a familiar species, the Northern White-breasted Hedgehog Erinaceus roumanicus was formerly classed as a subspecies of the Southern White-breasted Hedgehog E.concolor but has since been split. It is very similar to the species found in western Europe, the European Hedgehog E.europaeus, and has a similar fondness for human modified habitats such as parks, gardens and arable fields where a plentiful supply of insects and worms can be found. Unlike their western relative, they do not dig dens, instead making nests deep in grass. For the winter hibernation period they find dry areas under logs or other concealed and protected areas where they can sleep the winter away. They give birth in summer to 4-6 young, sometimes more, and have a lifespan in the wild of only a few years. Given its large range and generalist ecology, it is listed by the IUCN as Least Concern. 

Southern Water Shrew

There are at least seven species of shrew to be found in Ukraine, feeding voraciously as with all shrews on insects and sometimes small vertebrates. This last is especially true of the larger species such as the Southern Water Shrew Neomys anomalus, which regularly preys on frogs and small fish. As with many shrews it has venomous saliva, which incapacitates its prey. It is slightly smaller than the Eurasian Water Shrew Neomys fodiens, which tends to exclude it in areas where both are found. A wetland species it is vulnerable to habitat destruction and has a somewhat patchy distribution making local extinctions more likely, but is stall classed as Least Concern. 

Russian Desman

Unlike the solitary shrews, the strangest of Ukraines’ insectivorous mammals, the Russian Desman Desmana moschate seems to live in small social groups of up to five individuals. Technically a mole rather than a shrew, this semi-aquatic animal is functionally blind but compensates with a highly sensitive sense of touch. Although its main diet comprises various aquatic insects, they also feed on fish and amphibians and even take some plant material. Unfortunately they have quite specific habitat requirements, preferring shallow lakes or slow-moving rivers with dense waterside vegetation backed by primary forest, and this is in increasingly short supply. As a result the species is classed by the IUCN as Endangered. In Ukraine it is restricted to the north and west of the country. 

Steppe Polecat

The other large group of small carnivores in Ukraine are a wide variety of mustelids. Rivers and lakes are home to European Otter Lutra lutra, which in Ukraine may be locally threatened by pollution and habitat loss, but globally is Least Concern. Bother the Steppe (Mustela eversmannii) and European (M.putorius) Polecats can be found in Ukraine. M.putorius seems to prefer damper areas given the choice and in many parts of its range specialises in amphibians, whereas Steppe Polecats are true steppe specialists, feeding on ground squirrels, hamsters and marmots. They are highly nomadic, travelling miles each day in search of food and mostly staying in one place only until the local rodents have been reduced in numbers. It is likely that at some point in the distant past Steppe Polecats crossed the Bering land bridge to North America, where they became the ancestors of an iconic American small carnivore, The Black-Footed Ferret. They may also be the species domesticated as the domestic Ferret, much used in the past to hunt rabbits in England. 

European Mink

Despite its name, the European Mink Mustela lutreola is not at all closely related to the American Mink, but is instead a good native European species in its own right. Unfortunately a combination of habitat destruction and competition from American Mink has severely impacted its population, and it is now classed as Critically Endangered. At present only a few remnant populations can be found in a few of the rivers of the Carpathians in Ukraine. Part of the reason for its decline may be that it appears to be something of a dietary specialist on crayfish, and pollution and agricultural development has severely impacted wetlands and crayfish numbers in its range. 

Marbled Polecat

Finally, the most colourful of Ukraines mustelids is the Marbled Polecat Vormela pregusna. This has a range from eastern Europe across central Asia to China and south through the middle east as far as the Siunai Peninsula. It has a similar diet to the Steppe Polecat, but is more an animal of deserts, semi-desert and rocky areas where they feed on rodents, birds, and whatever they can catch. Destruction of steppe habitat has resulted in a population decline across its large range, which has put it in the Vulnerable category. The barren habitats where it mostly lives are not very productive of prey, so they need large ranges and have a correspondingly low population density.

Next time, I will look at the larger carnivores of Ukraine.

Ukraine Part 5: Dormice and Field Mice

 

Hazel Dormouse

Until I started this series I had no idea how rich eastern Europe and especially Ukraine is in rodents. Aside from this last group Ukraine also holds Eurasian Beaver and Red Squirrel, both widespread species. As well as those Ukraine is home to four different species of dormouse in the Gliridae and nine different true mice in the Muridae. The two groups are not very closely related and have quite different life strategies, with dormice often being very long lived and with fairly low reproductive rates, while true mice are short lived and are famously prolific.

Dormice are forest rather than grassland rodents, and as a result in Ukraine their range is concentrated in the north and west of the country, often in mountainous areas. They avoid steppe and agricultural fields, though some species will use orchards and scrubland and even enter houses.

Hazel Dormouse range

With a range extending from Britain well into Russia, and from Sweden south to Greece and northern Anatolia, the Hazel Dormouse as a species is currently listed as Least Concern. In parts of its range however, particularly in Britain, destruction of its habitat of deciduous woodland especially Hazel scrub has seriously impacted local populations and it is seriously endangered in Britain despite conservation efforts. Part of the problem is that Hazel Dormice do best in dense scrub with a rich variety of different shrubs and trees (they never feed on the ground but remain in the canopy) which provide a continually changing supply of high energy food, and in the past the practise of coppicing provided this easily. Coppicing is a means of ensuring a continual supply of growths from the stump of a still living tree. On a 10-20 year cycle “poles” would be harvested from the “stools” of the coppiced trees, which were usually hazel or sometimes willow, and used for agricultural fencing or charcoal production. This resulted in continuously regenerating hazel scrub, ideal for dormice. Today this has been abandoned except for conservation management and the dormice have lost their habitat. Although they mostly stay within 5m of the ground, they are quite squirrel-like in many ways and do not hesitate to climb high into the canopy if there is food there.

Beginning in spring, on emerging from their famously lengthy hibernation dormice first visit shrubs and vines such as Hawthorn and Honeysuckle to gain energy from nectar and pollen. In summer they eat vast amounts of insects, including aphids, and in the autumn they turn to berries and nuts, including Yew berries. Especially in summer food can be scarce in bad weather, and they handle this by going into torpor as they do in the winter. This energy conserving strategy means reproduction is delayed, and in Britain at least they only raise one litter of around four young a year, with perhaps only one or two surviving to breed. To compensate they are long lived, with survival over five years far from unknown. By comparison most wood mice and voles live less than a year on average. Aside from habitat destruction climate change is a potential threat. Ironically, warm winters, especially with variable temperatures, are very damaging as they interrupt the animals’ hibernation strategy which relies on near-freezing constant temperatures. Wet weather in summer also interrupts the life cycle as dormice have trouble feeding in periods of prolonged rain.

Edible Dormouse

While the mouse-sized Hazel Dormouse is a British native, the squirrel-sized Edible Dormouse Glis glis was introduced to Britain in 1902 to an aristocrats’ estate in the Chiltern hills in southern England. The species gets its English name from the ancient Roman fondness for eating them as a delicacy. Apparently in Croatia and Slovenia this custom persists to this day, and they are extensively trapped.

Edible Dormouse range

Edible Dormice prefer mature forest rather than Hazel scrub, and are particularly associated with Beech forest. Beech mast (seeds) are important for successful breeding and in poor years the animals may not even come into breeding condition – which is apparently triggered by the adults feeding on beech flowers in the spring. As with their smaller cousins they are quite omnivorous and shift their diet through the year. Before entering hibernation, which can last seven months or more, they put on a lot of weight, giving their alternative name of Fat Dormouse. Hibernation sites may be shared and where available often include crevices in caves, and they can descend deep into them in search of the right conditions. Failing that they can excavate their own burrows in dry soil and are reported from studies on the British population to seal themselves in entirely as protection against predators such as mustelids

As with other dormice they are long lived, over 12 years having been recorded even in the wild. Associated with this they take some time to reach maturity, probably not breeding until their third or fourth calendar year. There are usually only 4 or five young in a litter, and usually only one litter a year. They are quite territorial and are also quite vocal, with adults calling from high branches to mark territory. Natural enemies would be mustelids such as Beech and Pine martens and various raptors, especially owls.

Forest Dormouse

Midway in size between the Hazel and Edible Dormouse, the Forest Dormouse Dryomys nitedula is found away from agricultural areas in a variety of forest types, including coniferous forest, and often at high elevations. In Europe the densest population is in Moldova, but its range extends eastward through Iran and Afghanistan into western China. As with other dormice it is omnivorous and long lived. The specific name nitidula “nest builder” refers to the large nests, similar to the drey of a squirrel, that they construct from twigs to give birth in. Whether or not they hibernate, and for how long, depends on the local climate, with individuals in Israel remaining active year-round.

Forest Dormouse range

Garden Dormouse

Of a similar size to the Forest Dormouse, the Garden Dormouse Eliomys quercinus is slightly more terrestrial than other dormice and is often found in rocky areas. It is commonest in warmer climates around d the Mediterranean, and several islands have endemic subspecies. It has declined more than any other European rodent, especially in the east, and in Ukraine there are only a few areas whgere it can be found. As a result it is classed as Near Threatened by the IUCN, whereas other European dormice are all least Concern. Although omnivorous like its relatives, its diet does seem to include more animal protein than vegetable. It preys upon large insects, birds eggs and nestlings, and even smaller rodents, but will also feed on various fruits and nuts.

Garden Dormouse range

Northern Birch Mouse

Most closely related to the jerboas, although of a far more normal small rodent appearance, two species of birch mice are found in Ukraine. Although closely related, the Northern Birch Mouse Sicista betulina and the Nordmanns Birch Mouse Sicista loriger prefer different habitats and have different ranges.

Northern Birch Mouse range

The Northern Birch Mouse has a range extending from Scandinavia east to Lake Baikal, and south to the Carpathian mountains. As a result it is on the southern edge of its range in Ukraine, where it lives in coniferous or mixed deciduous woodland and wet scrub. It hibernates in the winter for seven or eight months, and during the summer produces usually only a single litter of up to six young. They feed mainly on various plant material but also take insects, earthworms and snails. In the western part of its range it is uncommon, but it is frequent in the east and as a result is classed as Least Concern. Its only real threat would be deforestation and possibly climate change.

Nordmanns Birch Mouse

By contrast Nordmanns’ Birch Mouse is an animal of much more open habitats, preferring steppe, open woodland, and even semi-desert. They do not dig their own burrows but use natural holes or crevices. Like their northern relatives they hibernate many months each year. Also unlike their relatives, they have a very restricted range mostly in the grasslands east of Odessa with a few isolated populations known in Moldova and Romania, plus one part of southern Russia. As a result of this fragmented and probably declining population they are listed as Vulnerable, and are at risk of agricultural development and habitat destruction.

Nordmanns Birch Mouse range

Dormice and Birch mice are both old groups of rodents, with various Birch mice known from as long as 17 million years ago, and various dormice from even longer ago. These ancient groups of rodents tend to have fairly low reproductive rates and long lifespans, a life strategy adapted to relatively constant and predictable habitats. During the Pleistocene the rapid climate fluctuations has suited the evolution of species with high birth rates and short lives that can rapidly take advantage of new conditions, and in Europe the various Apodemus Wood Mice are classics of this type. Ukraine is home to five species, which between them exploit habitats from grassland to closed canopy woodland, although woodland edge with its wide variety of food usually hold the greatest numbers. Apodemus species are mostly terrestrial, although they are agile and will climb into bushes for berries and nuts as well as insects and other food. They can have five litters a year of six or more young, so populations can rapidly explode in good conditions.

Striped Field Mouse

An example of this type is the Striped Field Mouse Apodemus agrarius, which seems to be currently expanding its range westwards (it reached Austria in the 1990’s) Fairly large for an Apodemus species, it can weigh 50g and 120mm long. As well as being a serious agricultural pest on occasion they also harbour a variety of dangerous viruses which are a risk to human and animal health. It exists in two separate parts of the world, an eastern population in eastern China and the second population centred in eastern Europe west to Italy and Germany. The range expansion is most likely due to creation of farmland from forest, which opened up new habitat.

Striped Field Mouse range

Yellow-Necked Mouse

By contrast the Yellow-Necked Mouse Apodemus flavicollis is a true European species. With arrange from southern Britain into Russia west of the Ural Mountains. They prefer woodland or forest edge and are great hoarders of acorns, hazel nuts and other large seeds. They dig extensive burrow systems and will also climb into bushes or even enter houses.

Yellow-Necked Mouse range

Eurasian Harvest Mouse

Given its truly gigantic range – it extends from Britain to Vietnam – The Eurasian Harvest Mouse is listed by the IUCN as Least Concern. Despite that, changes in farming practises have caused declines in many parts of their range and in Britain they are a protected species. Their original favoured habitat was probably tall grassland and reedbeds, which they still favour today. They need permanent dense vegetation to make their winter nests in and large agricultural fields are useless to them in the winter. In the spring they climb up, helped by their prehensile tails, and make their nests suspended in the grass or reeds in which they raise their large litters of young. They are truly tiny animals, no bigger than 11g and usually half that.

Harvest Mouse range

Steppe Mouse

One final rodent to be found in Ukraine is the open-country relative of the common House Mouse, the oddly-behaving Steppe or Mound-Building Mouse Mus spicilegus. They are classic steppe and open country animals, found from Austria east into southern Ukraine and south into Greece. These animals are hard to tell apart from House Mice until they are observed in the autumn. At this time of year up to fourteen mice cooperate in gathering a mound to protect their winter food stores. 

Steppe Mouse mound

These mounds are usually one or two metres across, but mounds up to 4m across have been recorded, and when freshly built can be 50cm high. Given the short life spans of these rodents the mounds are actually built by the young of the year when they are only a few weeks old. The storage chambers within the mounds can hold 10kg of food. Vegetation is also incorporated into the structure of the mound, and it is possible that fermentation of this generates heat to keep the nest builders warm. They are only social in the winter – during the summer breeding season they become at least socially monogamous with significant paternal care and females become quite aggressive to rival females.

Steppe Mouse range

This concludes the survey of the rodents of Ukraine – next time I will turn to the small carnivores that prey on them.

Ukraine Part 4: Hamsters, Voles and others

 

Common Hamster preparing to attack

The Golden Hamster is a popular pet with children, although to be honest other rodents are better choices, and when I was a child we had a succession of them in the house. Definitely not suitable as a pet is the cavy sized (maximum 450g) Common Hamster Cricetus cricetus, which is notorious for a decidedly aggressive disposition. Try to pick one up and it will not sit placidly in your hand but rather try to bite it off. This is probably an inevitable result of being a handy sized meal for basically every carnivorous mammal or bird in Europe, and being decidedly territorial and solitary as well.

Common Hamsters despite their name are becoming increasingly uncommon, to the point of being classed as Critically Endangered. Their range before their recent decline extended from eastern France to Kazakhstan, and Poland to Georgia. A classic grassland animal, they adapted well to the rise of agriculture to the point of becoming a serious pest, and as a single hamster can store as much as 65kg of grain in the depths of its burrow then it easy to see how it has historically been persecuted. The recent rise of industrial agriculture however has had a serious effect, not least because modern crops tend to be cleaned of the agricultural weeds that are vital to its diet – in fact a lack of vitamin B3 in the diet due to living exclusively on maize is associated with behavioural abnormalities including infanticide.

In normal circumstances Common Hamsters live in a burrow that during the winter may be several metres deep. They prefer deep, heavy soils where burrow construction is easiest. Each hamster has its own burrow which it defends vigorously, only meeting another hamster to mate. After a very short pregnancy of only 18 days the female gives birth to up to 15 pups, although usually less, and in the course of a summer usually has two litters. Clearly maximum productivity is potentially very high, and they need to have this ability as foxes, mustelids, various raptors both diurnal and nocturnal, and probably many snakes will prey on them.

In Ukraine until the 1990’s Common Hamsters were widespread and common, especially in the forest steppe zone away from the drier soils of the south east. Densities reached up to 7 burrows per hectare. Since then there has been a major decline, and they are effectively extinct over much of the country. The chief reason for this is probably changes in agricultural crops – they much preferred alfalfa fields to cereals and decline in cattle with inevitable decline in need for alfalfa forage has removed habitat. Burning of fields and use of pesticides and herbicides has also removed much of their food and habitat.

Grey Dwarf Hamster

Also present in Ukraine is the much smaller Grey Dwarf Hamster, Cricetulus migratorius. A much smaller animal, it averages around 10cm long and 40g or so – about 1/10 of a Common Hamster. This is much more a dry country animal, living in areas of open vegetation and semi-desert, often at high altitudes and avoiding wetter areas. In many parts of its range, which extends east from Ukraine into western China and south into the Middle East it is associated with people, sometimes even living in houses, Unlike its giant relative it is listed as Least Concern, and as it is not so dependent on good farmland that state is unlikely to change. In other ways it is similar in behaviour, being a solitary animal living in burrows and making extensive stores of food for hard times.

Steppe Lemming

Much less solitary than hamsters are the so-called Steppe Lemmings Lagurus lagurus. Technically a vole, these tend to live in family groups with each family having a main domicile burrow with several entrances and a nesting chamber. Each family will stay close to the burrow, usually within 6m of their home. As with their Arctic counterparts they have extreme fluctuations in population, and can build up their numbers rapidly when conditions are good. As they can have six litters of up to seven young a year population explosions can occur, and when this happens large numbers will disperse in search of food in the form of seeds, bulbs and other plant material. Today it is an eastern species with Ukraine marking the western end of a range through Mongolia into China, but fossil remains show that in the cold and dry habitats south of the ice sheets during the Ice Ages its ranged extended as far west as the British Isles.

Tatra Vole

Many species of Microtus voles are found in grasslands and fields across Europe. Ukraine is home to six species, but one of the least known is the Tatra Vole Microtus tatricus. Ukraine and Romania share a unique subspecies M. tatricus zykovi. Unlike the previous species, this very much avoids farmland and is only known from natural habitats such as alpine meadows, often at high elevation.

Snow Vole

Living well away from the grassy fields of the lowlands, the Snow Vole Chionomys nivalis is an animal of rocky areas above the tree line. As with many small rodents it is mostly solitary and territorial and feeds on green plants, seeds and a few insects. They tend to use scree slopes and dig burrows among the rocks. They are active both by day and by night, and may bask in the sun on occasion. They have a wide range in European and Asian mountains, as far west as Portugal and as far east as Turkmenistan

Thick-tailed Three Toed Jerboa

Not related to the various members of the hamster and vole family, a Ukraine species that is hard to confuse with any other small rodent is the Thick-Tailed Three Toed Jerboa, Stylodipus telum. Growing to abody length of around 11 cm, with a tail as long again, the rather unwieldy name is at least descriptive of a species that has a method of locomotion that is instantly recognizable – they hop. They live in deserts and desertified steppes, and Ukraine is at the west end of their distribution which extends through central Asia into China. They live in complex burrows with multiple entrances/ exits. . The reproductive rate is low for a rodent, with only a single litter of up to six young each year. They are almost entirely nocturnal, leaving their burrows to hunt for seeds and insects. Although fairly widespread, the subspecies found in Ukraine S. telum falz-feini is fairly rare and at risk from agricultural development and pesticides.

Next time I will look at the remaining variety of rodents in Ukraine. The dormice and field mice