Many of the birds we have in the UK are migratory species that either breed here and leave in the winter to warmer climates or spend the winter here in order to escape even colder climates to the North and East. However, there is still much we do not know about how, when, where and why birds migrate. We know even less about bat migration, with three species found in Britain known to migrate, but little known about where they migrate to and from. Furthermore, many migratory bird and bat species are declining, due to anthropogenic pressures, such as: habitat loss, global warming, and persecution.
A large collaboration of scientists and conservationists have been working together to advance research into migratory bats and birds in the UK by building a network of receivers that can track them through the installation of tiny radio transmitters fitted to the animal. These transmitters weigh only 0.3g, so even very small creatures can carry them without detriment to their performance. When a tagged bat or bird passes within range of a receiver (2-15 km depending on the terrain and how high the animal is flying), the receiver automatically logs the presence and direction of flight of the animal. If there is a large network of such radio-receiving stations, we can detail there movement over large areas and timescales. This collaborative network, named “Motus Wildlife Tracking System” was designed in Canada and can provide researchers with valuable data on birds such as, migratory routes, lifespan, dispersal and foraging behaviour. Motus is already being used in continental Europe and there are already many of these receivers in Germany, the Netherlands, Belgium, Norway, Sweden, Austria, Hungary, Spain, Portugal, Italy and Morocco (https://motus.org/data/receiversMap). Therefore, expanding this network into the UK can deliver fascinating information about the movements of migratory animals across Europe, an idea simultaneously designed at Spurn Bird Observatory, on Yorkshire’s east coast and across the water in the Netherlands.
Initially, two research questions will be investigated using the Motus network. One, led by the University of Hull, the British Trust for Ornithology, the Institute of Avian Research “Vogelwarte Helgoland” and the Bird Observatories Council, will seek to investigate the recent trend of increased westward Yellow Browed Warbler migration. This species usually breeds in Siberia and then migrates to South-east Asia to avoid the harsh winters. However, recently they have been seen in increasing numbers migrating in the opposite direction, through northern (continental) Europe, into Britain, and with sightings thereafter in south-west Europe and even western Africa. By tagging these birds and recording their direction of migration using the Motus network, as well as doing genetic and stable isotope analysis on feather samples, researchers hope to find out more about where and why these birds are changing their migratory patterns.
The second project, led by Wageningen University & Research, in the Netherlands, in cooperation with the Bat Conservation Trust and Norwich Bat Group, seeks to find out the migration route of the bat species, Nathusius’ pipistrelle. The movements of bats in and out of the UK and their overseas migration routes and origins are very poorly understood. Scientists hope to track these bats across their range, in addition to assessing the potential threat of offshore wind farms to their survival. The findings will be used to aid the conservation of bats across their migratory route.
Recently, researchers from Wageningen University, the University of Hull and Norwich Bat group, installed three receivers in East Anglia, with several more planned to be installed in England and Wales by the UK Bird Observatories before this year’s autumn migration.
Overall, the UK Motus network has the potential to increase our understanding and help conserve many species of both bats and birds. Bird and bat groups across Britain can become involved and own their own receiver station. The installation of receiver stations in Britain is being overseen by a Strategic Steering Committee involving the University of Hull, BTO, and the Bird Observatories Council. Any such groups or individuals interested in joining the scheme should register with the committee by contacting Dr Adham Ashton-Butt (firstname.lastname@example.org) for further information.
The findings of the initial UK projects and future projects will be eagerly awaited by scientists, conservationists and nature lovers alike.
Dr Adham Ashton-Butt
University of Hull
Motus aerial installed on Caister Lifeboat station
Aerial pointing out to sea, hoping to receive transmissions from a tagged bird or bat
Motus aerial being installed on the CEFAS laboratory in Lowestoft
Below: Motus aerial installed at Landguard Bird Observatory, Suffolk