In search of the Giant Noctule – Europe’s biggest bat
This summer, experts from APB-Birdlife Belarus set out on their fourth annual fact-finding expedition to the remote marshes of Paliessie in search of a rare bat species, the Giant Noctule.
After its first recorded sighting in Belarus, back in 1930, the elusive Giant Noctule Nyctalus lasiopterus was never to be seen in the country again throughout the rest of the 20th century. No wonder scientists were so excited, in 2015, to rediscover its presence in Stary Žadzien, a remote forest and wetland area in Paliessie, south Belarus. This finding established a new northern range limit for the species whose breeding grounds are found in Hungary in the west and in the Ural Mountain in the east.
The Giant Noctule, weighing 80g and with a wingspan of up to 46cm, is Europe’s largest bat. Amongst the small number of bat species that prey upon small birds, it has a unique hunting style, targeting passerines in flight rather than at their nests. A rare species, it is also one of Europe’s least studied bats and its conservation status is listed as ‘Vulnerable’ by the IUCN.
For the past four years, APB-BirdLife Belarus has been conducting scientific expeditions to study the bats in their new habitat here at Stary Žadzien – an internationally recognised protected site under the Ramsar Convention and an IBA (Important Bird & Biodiversity Area) home to the globally threatened Greater Spotted Eagle Aquila clanga. The goal of the latest expedition, which took place this summer, was to take genetic samples and tag the bats with transmitters which will subsequently tell us about their movements and their roosting sites.
"The Giant Noctule, weighing 80g and with a wingspan of up to 46cm, is Europe’s largest bat"
Bat behaviour is, quite literally, as changeable as the weather. In good conditions, activity begins at dusk, continuing throughout the night and peaking at dawn. In the evenings, APB experts and volunteers set nets along a marsh river – where several different species of bats are known to drink and hunt – and took it in turns to keep watch for successful catches. In rainy or foggy conditions, flight is a struggle and so detectors were used to trace their nests. In one instance, volunteer Raman Shkabara scaled a pine tree to reach a 10m high tree hollow housing four individuals. Back at the campsite, the bats were identified and measured and transmitters were attached to key species of interest –Northern bat Eptesicus nilssonii, Parti-Coloured bat Vespertilio murinus and 11 Giant Noctule.
Thanks to such expeditions, we now know that the Giant Noctule’s hunting ground in Belarus spans a range diameter of up to 30 km. Researchers also discovered that the bats are attracted to old burned areas, with transmitter data showing that they spend a relatively long time hunting in such areas at night.
Though a new arrival to Belarus, the Giant Noctule can tell local conservationists a lot about the biodiversity status of its new habitat. "The Giant Noctule is basically linked to the natural state of forests and marshes", says Viktar Fianchuk, conservation coordinator of the joint program between APB-Birdlife Belarus and the Frankfurt Zoological Society. "For these bats, it is important that the natural area is undisturbed, which means that the landscape has not been changed and there are many old trees."
Unfortunately, this may not be the case for much longer. As reported by BirdLife earlier this summer, a new road is being built through Almany Mires – a mere 20 km away – is wrecking devastation upon one of Europe’s most ancient and important bogs. Deforestation and draining here may bring severe knock-on effect to Stary Žadzien’s delicate ecosystems. As APB-BirdLife Belarus continues its efforts to stop the bulldozers, it hopes that the Giant Noctule’s return to Belarus only reinforces the importance of protecting such rare habitats from human destruction.
Alesia Basharymava - Communication Officer, APB BirdLife Belarus