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Murin à oreilles échancrées
MURIN À OREILLES ÉCHANCRÉES
Medium sized, Geoffroy's Bat (Myotis emarginatus) has dense, woolly fur, red on the back and lighter on the belly. His brown nose is in the form of a mouse’s nose. Its characteristic brown ears are a very pronounced external feature.
Longevity: Up to 16 years (longevity record = 18)
Size: 4.1 to 5.3 cm
Average ear size: 1.4 to 1.7 cm
Wingspan: 22 to 24.5 cm
Weight: 6 to 15 g
ECOLOGY AND BIOLOGY
Geoffroy's Bat frequents low-lying areas.
His hunting area is diverse, it can be characterized by woodlands and bushy areas (sub-hardwood: oak, alder, willow), as well as open forest environments (forest paths, clearings, tree-lined rivers) , large isolated trees or small islands of vegetation near the living area. It also hunts over rivers and the water seems to be an essential element in its existence. The presence of livestock is very favourable to the species: Geoffroy's Bats commonly hunt in barns, and sometimes establish their breeding ground there. In a Mediterranean environment, it also hunts insects over traditional olive groves.
Some of the hunting grounds are shared with the Greater Horseshoe Bat (farmland, pastoral areas).
A twilight and nocturnal mammal, a fast and agile flyer, he moves at a medium height and uses echolocation to hunt his prey.
His diet is unique among the bats of Europe and demonstrates a significant specialization of the species. It feeds mainly spiders and flies. Other prey (Coleoptera, Hemiptera and Neuroptera) are eaten occasionally and reveal opportunistic behaviour.
Geoffroy's Bat is sedentary, and moves between the breeding area and the hibernation ground. The species can usually travel to up to 40 km on average (known maximum displacement is 106 kms).
In summer, it sometimes goes as far away as 10 km from the breeding ground, to hide in natural cavities such as holes in trees. It is therefore very difficult to observe during this period. The breeding sites, mainly attics or roofs can accommodate 100 to 300 females. These areas are often shared with the Greater Horseshoe Bat . The emergence of female Geoffroy's Bats to hunt is at twilight or later. They usually fly to hunt in complete darkness, most often an hour after sunset.
In winter, these are the first bats to reach hibernation cavities and the last to leave. In fact, they are the last to resume spring activity, the majority still dormant at the end of April. From November to March-April, Geoffroy's Bats hibernate in underground cavities, natural or artificial caves, mines, caves, tunnels. These large areas have the following characteristics: total darkness, temperature below 12°C, relative humidity close to saturation, and very low to no ventilation.
Regularly in small groups or swarms, the species is generally suspended from the walls and rarely go into fissures or cracks.
Female gestation lasts between 50 and 60 days. They produce one young per year, between mid-June to late July. The birthing period is later than other species because it is synchronized with the peak population of its main prey. Young Geoffroy's Bats are kept in underground cavities or buildings, where females form breeding colonies of variable sizes, regularly with another species, the Greater Horseshoe Bat, creating a favourable microclimate. The young are able to fly at the age of 4 weeks.
Geoffroy’s Bat is a very vulnerable species. Its sedentary lifestyle within its various grounds makes it highly dependent on human activities, and it suffers from the increasing light pollution.
Geoffroy’s Bat population may be threatened by:
- The loss and alteration of breeding grounds(demolition of buildings, modification and toxic treatment with a roof, illumination of churches, modernization of old buildings incompatible with the presence of bats...),
- The repair, modification or closing of hibernation grounds (caving in mines, untimely visits of caves...),
- The modification and / or loss of hunting grounds,
- Road mortality (collisions with vehicles),
- Chemical treatment of agricultural and forestry plots and treatment of livestock against pests.
DISTRIBUTION AND THE STATE OF THE POPULATION
Globally, Geoffroy’s Bat is present in Europe. (south of a line Belgium- Romania), Asia Minor and northwest Maghreb. Populations are stable and the species is in category LC ("Least Concern") on the global Red List of Threatened Species (IUCN, 2008).
Source : IUCN (International Union for Conservation for Nature). Myotis emarginatus. In : IUCN 2011.IUCN Red List of Threatened Species. Version 2012.1
In Europe, the species has declined significantly between 1960 and 1990, but more recently its numbers and its range are stable or increasing. It is therefore classed LC ("Least Concern") on the European Red List of threatened mammals.
In France, the situation for Geoffroy's Bat has strong regional disparities. They can be abundant in certain ares (valleys of the Loire and Cher, Charente-Maritime) but rare elsewhere. However, counts, conducted over 10 years of this species in winter, show a slow but steady increase in numbers since 1990. It appears in category "Least Concern" by the IUCN Red List of endangered species in France (France & MNHN IUCN, 2009).
In the Camargue, there is little hibernation likely due to an absence of favourable cavities ( no hibernation colony is known off in the Provence-Alpes-Côte d'Azur and Languedoc-Roussillon regions ). The number of individuals is 410 in three living areas, all included within the framework of LIFE, therefore 100% of the known population. All of the colonies have been discovered recently, which means there is no reliable track of the population trend. However, it is emphasized that one colony is threatened in the short term and another is in a vulnerable position.
In the Alpilles, 140 individuals divided into two cavities, all included within the framework of LIFE, therefore 100% of the known population. The conservation status of the population is poor: the breeding population in one of the cavities has decreased by over 50% since the 90s.
In the Gardon gorges, the scarcity of buildings on the site makes the presence of a colony unlikely in the SCI (sites of common interest). The number of individuals is 600, all included within the framework of LIFE. Counts conducted in recent years show that the numbers in the colony are stable. However, its future is threatened in the short term (sale of barns).
For the entire area covered by the LIFE+ Chiro Med program, the breeding population of Geoffroy's Bats is at least 1150 individuals. In the Provence-Alpes-Côte d'Azur regions, 1,155 breeding individuals were identified in seven colonies (database, GCP, 2008) in Languedoc-Roussillon, 2700 individuals in nine colonies (database GCLR, 2008), in Corsica, 7000 in 20 colonies. The total for France is 12 005 individuals. In the Camargue the breeding population represents 30% of the Provence-Alpes-Côte d'Azur area, and those within the LIFE + Chiro Med Project, 10% of the breeding population in the French Mediterranean.
In conclusion, besides the importance of effective breeding, actions undertaken by the project on behalf of this species are logical and consistent with the fact that it shares its breeding sites and many of its foraging habitats with the Greater Horseshoe Bat.