482.

Daubenton’s Myotis

Myotis daubentonii

French: Murin de Daubenton / German: \Wasserfledermaus / Spanish: Ratonero ribereno

Other common names: Daubenton’s Bat

Taxonomy. Vespertilio daubentonii Kuhl, 1817,

Hanau, Hessen, Germany.

Subgenus Myotis; daubentonii species group. Phylogenetic studies in 2013 and 2015 recovered M. daubentonii in a clade with M. sicarius, M. bechsteini, M. longicaudatus, M. soror, and M. frater . Monotypic.

Distribution. Most of Europe and W Asia, from S Fennoscandia, British Is, and Iberian Peninsula E to W Russia (E to Omsk region), the Caucasus, and N Turkey; disrupted distribution in Mediterranean areas.

Descriptive notes. Head-body 45-55 mm, tail 27-50 mm, ear 9-14 mm, hindfoot 9-11 mm, forearm 33-42 mm; weight 6-10 g. Daubenton’s Myotis has grayish or brownish dorsal and ventral hairs, with dark bases and more brighttips, sometimes reddish. Wings are generally dark brown or gray. Young are generally darker than adults. Plagiopatagium starts at base of fingers, Uropatagium is naked; venter is slightly lighter but not white. Earsare relatively small and triangular, with 4-5 folds. Tragusis straight, short, and sharp and barely reaches one-half of ear length;it is whitish, with blackish tip at top and bends forward. Feet are relatively large (equally as long as tibia), covered by long fur or bristles. Atfirst sight, Daubenton’s Myotis might be confused with the Common Whiskered Myotis ( M. mystacinus) or Brandt's Myotis ( M. brandtii), but it has shorter feet. Skull is relatively flat and broad with weak sagittal and somewhat strong lambdoidal crest. P° lies within tooth row; upper molars have developed protoconules; and lower molars are myotodont. Chromosomal complement has 2n = 44 and FNa = 52 (Greece, Germany, and Spain).

Habitat. Mostly riparian habitats and water ecosystems (natural and artificial water), urban areas, forests, parks and traditional orchards from sea level up to elevations of ¢. 1400 m. Daubenton’s Myotis usually commute through woodlands (where they roost) to reach water where they feed. They can also be abundant in wetlands, rocky areas, inland cliffs, mountain peaks, and deciduous and mixed forests.

Food and Feeding. Daubenton’s Myotis is specialized to hunt just above calm water surfaces of streams, rivers, ponds, or lakes, being remarkably more abundant along open banks. They hunt ¢. 5-40 cm above the water surface, which makes trawling and capturing insects from the water surface easier. They move to hunting areas in groups of 2-6 individuals, but hunting is mostly done alone. They also hunt in meadows, open spaces, grasslands, and forest edges. It has been considered a specialist and generalist because it hunts Diptera opportunistically in some regions but also some Hymenoptera, Hemiptera, and Lepidoptera, very specifically in others. It has been shown experimentally that it can successfully hunt fish from the water.

Breeding. Maternity colonies of Daubenton’s Myotis are formed in late spring (May or early June), generally in tree holes (hollow trees, rotten branches, abandoned woodpecker nests, etc.) and also bat boxes, bridges, and buildings. Maternity colony range from a few tens to a few hundred females and their young; some locations have up to 600 individuals. Females reach sexual maturity after the first year of their life. Small maternity colonies tend to change location after 3-5 days to avoid predation pressure, which means that a single nursery colony can use up to 40 tree holes/year. After parturition (with generally one young), females tend to forage in less than a 2-5-km radius around the roost. Young are commonly born from mid-June to July, depending on weather and region. In general, they need c.3—4 weeks to start flying. During the maternity period, solitary males or small groups of males will roost in the maternity colony or elsewhere in cellars, mines, or tunnels. Breeding season usually ends in August. During mating in September—November (particularly intense in October-November), they are most commonly found at swarming sites (e.g. caves, mines, or buildings) where large numbers of individuals converge to mate after traveling up to 30 km. Maximum reported longevity is c.4 years, butit is assumed it can live longer similar to some congeners.

Activity patterns. In winter, most roosts are caves, mines, and other underground sites with temperatures of 3-8°C, but some individuals also roost in tree holes and deep cavities in hollow trees, caves, bunkers, and mines. Echolocation calls have short, highly modulated pulses, starting at more than 60 kHz and ending below 30 kHz (broad frequency range), with frequency of maximum energy of c.40 kHz. When they emerge at night, usually after sunset, they move along linearstructuresin the landscape such as forest corridors, ditches, edges,trails, etc. During the non-breeding period, individuals can fly up to 10 km /night in straight line to reach hunting areas.

Movements, Home range and Social organization. Daubenton’s Myotis is considered non-migratory but will move ¢. 150-304 km from maternity roosts to hibernation sites. Individuals from lowland regions are assumed to move longer distances than those roosting in high mountains. Especially in the north-eastern part ofits distribution, they congregate in winter in large numbers (e.g. 20,000 in Nietoperek, Poland or up to 5000 individuals in Berlin, Germany).

Status and Conservation. Classified as Least Concern on The IUCN Red List. Daubenton’s Myotis is one of the most abundant species in many parts of its distribution, especially in Central and Eastern Europe. Some monitoring programs suggest that its distribution and population are increasing, but fluctuations in numbers can be extreme depending on the area studied.

Bibliography. Akasaka et al. (2009), Bogdanowicz (1994), Boonman, A.M. & Jones (2002), Boonman, A.M. et al. (1998), Boonman, M. (2000), Britton & Jones (1999), Dietz & Kalko (2006), Dietz et al. (2006), Encarnacao & Dietz (2006), Encarnacao, Becker & Ekschmitt (2010), Encarnagéo, Dietz & Kierdorf (2004), Encarnagao, Dietz, Kierdorf & Wolters (2004), Encarnacao, Kierdorf et al. (2005), Flavin et al. (2001), Jones & Kokurewicz (1994), Kokurewicz (2004), Kriiger et al. (2012), Lépez-Baucells, Casanova et al. (2017), Luan & Radil (2010), Parsons & Jones (2003), Russo (2002), Shirley et al. (2001), Siemers, Dietz, Nill & Schnitzler (2001), Siemers, Stilz & Schnitzler (2001), Siivonen & Wermundsen (2008), Simmons (2005), Stubbe, Ariunbold, Buuveibaatar, Dorjderem, Monkhzul, Otgonbaatar, Tsogbadrakh, Hutson et al. (2008), Vesterinen, Lilley et al. (2013), Vesterinen, Ruokolainen et al. (2016), Volleth & Heller (2012), Warren et al. (2000).