Rhinolophus blasii (Peters, 1866)
Rhinolophidae

Least Concern

Description

A medium-sized hosershoe bat, it is similar in size to the Mediterranean horseshoe bat (Rhinolophus euryale) and the Mehely's horseshoe bat (Rhinolophus mehelyi). This species has a forearm length of 42.5 to 50.1 mm, a wingspan between 270 to 310 mm and usually weighs 10 to 14 gr. The fur is pale brown but can also be sand-coloured or yellowish. A characteristic of adult Balsius' horseshoe bats is that the white base of the hairs is particularly visible. The ventral fur is only slightly paler than the dorsal pelage.

It can be easily differentiated from the greater (Rhinolophus ferrumequinum) and lesser (Rhinolophus hipposideros) horsehoe bats by it's medium size. The other two medium-sized horseshoe bat species can be identified by characteristics of the noseleaf and the length of the phalanxes.

Distribution

The species has wide range in the Palearctic and Africa, but it is highly patchy and fragmented. In Europe it is limited to the south-east, including the enitre eastern Adriatic coast, parts of Serbia and Montenegro and within the southern Carpathian  basin of Romania, Bulgaria, Greece and Turkey as well as some Mediterranean islands (Crete and Cyprus). The species is probably extinct in Italy and Slovenia. It is also found in Asia Minor and North Africa.

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Roosts and phenology

It roosts almost exclusively in karst caves, which are inhabited all year round. Single animals can be found in mines and other underground roosts. This species forms nursery colonies of 30-500 animals. In southern Bulgaria there were up to 3,000 animals in some years. Adult males can be usually found in nursery roosts, and they hang in numerous clusters and, before birth time, males and non-reproducing females can constitute up to a third of the animals in a breeding roost. While they do form single-species colonies it is usually found in mixed clusters with Mediterranean (Rhinolophus euryale), Mehely's (Rhinolophus mehelyi) and greater (Rhinolophus ferrumequinum) horseshoe bats, greater (Myotis myotis) and lesser (Myotis blythii) mouse-eared bats and bent-winged bats (Miniopterus schreibersii) and long-fingered bats (Myotis capaccinii). In Bulgaria, births take place in late June, with only one young per female. In the Rhodopians, some lactating females can still be found in the middle of September. Sexual maturity is probably reached in the second year.

It is largely a sedentary species, with summer and winter roosts usually in different but close-neighbouring caves. It can probably perform seasonal movements of up to 100 km. Mating takes place at least partly in September. Males hang in caves in front of females and display with flapping winfs and court her before mating. Hibernation cave temperatures are usually between 13.8 to 17°C.

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Habitat and diet

A species of typical Mediterranean landscapes with small-scale mosaic combining open habitats and shrublands. Usually occurs in lower altitudes and hunts in scrub and low-growing hornbeam and oak forests along edges in highly structured landscapes. It has a preference for broad savannah-like habitats with open wooded vegetation and narrowly linked open zones.

In Bulgaria and Greece, some studies found that in summer it almost feeds exclusively on moths. Moths usually comprise 95-100% of the dietary components. It feeds mainly on the wing, circling around shrubs and edges at 0.5 to 5 meters height. Blasius's horseshoe bats are extremely agile and can easily catch prey close to vegetation or pick prey directly from the ground. It usually hunts within less than 10 km from the roost.