New Forest Bechstein’s & Barbastelle Survey
Dates for the project surveys are normally every 2-3 weeks. Surveys largely focus around attempting to catch bats and then radio track them. Once bats are caught and tagged people are needed to help track or at least locate bats every day. Tags last up to 3 weeks and so willing helpers are required to help with this as well as coming out to experience the catching!
We need to limit numbers on catch nights so please email Colleen Mainstone if you are interested in any of the dates noted on the website. To ease admin, dates will normally be posted on this website.
If you are interested please email Colleen. Locations will only be given once a place is confirmed.
Background:
The aim of this project is to investigate the status and distribution of these two rare species of bats in the New Forest.
Since first hearing Barbastelle bats in autumn 2005, we have spent much of 2006 broadening our search for both Barbastelle and Bechstein’s bats. The method is based on the use of an ‘autobat’ which plays social calls of target species in the close proximity of nets or harp traps. When bats are caught they are processed in the normal way but one or maybe up to two female Barbastelle or Bechstein’s bats are fitted with radio transmitters and their movements followed over the ensuing nights and days. The method is very effective at finding roosts; at certain times of the year one can assume that large gathering of bats are maternity roosts, (or roosts of juveniles) at the very least they represent a core area for a population. We do not tag pregnant or lactating bats for welfare reasons. Bats move roost sites regularly so a number of roosts are recorded.
The behaviour of female Bechstein’s bats has been researched by Frank Greenway, David Hill and a number of other researchers. Bats remain largely within a core foraging area of 1-2km at most from their roost sites. Males roost and roam more widely. Once we have located Bechstein’s in such a way we assume that the surrounding 1-2km forms the habitat for their colony and we move on to establish other colonies in different areas. Barbastelles roam far and wide – up to 30 km a night but on average 8km from roost sites. Colony areas for this species are therefore trickier to establish.
2006 year started well with a male Bechstein’s bat and then within a few days a female off the Rhinefield Drive. Named David and Madge after former bat group members we then went on to establish a further two more southerly colonies of Bechstein’s bats (7 and 10km away from each other) and towards the end of summer a colony of Barbastelle bats near our original Bechstein’s colony. An average of 3 tree roosts were located for each tagged bat; frequently with different numbers of bats emerging or returning on different occasions.
Bechstein’s bat caught in net
Bechstein’s roost tree – up to 30 bats seen emerging Up to 25 different volunteers got involved to varying degrees with a core group of 4 or 5. Bat detector surveys are a useful survey method for Barbastelles but not of value for Bechstein’s which are quiet on a detector and often forage in the canopy. Counting of tree roosts on a regular basis is a non-intrusive way to monitor the use of known tree roosts. Night vision binoculars or night shot video are required as the trees are frequently in darker areas of the woodlands. A few people helped us to monitor radio-tracked animals.
In late autumn we were pleased to receive funding from the New Forest National Park Sustainable Development Fund for £18,000 and the New Forest Trust for £2000. The funds will provide for much needed equipment; as you can imagine this kind of survey technique is not cheap. The resources will be used to purchase more radio tracking equipment, tags, night vision, bat detectors, laptop and software to analyse bat calls and survey data and boost our supply of nets and poles. It will also pay for training course venues and publicity; we are planning a number of talks in autumn 2006 and spring 2007. There will be a training course for interested volunteers in late April/early May 2007. Matched funding for the grant monies has been committed by bat group members – time assisting us with the project will be valued at £10.85 an hour…. we need to work for 300 days by March 2007!…. realistically achievable as we intend to repeat this survey methods 2-3 times a month during the achieve bat season. As project organisers our time planning surveys and doing daytime Forest habitat assessment and report writing also counts.
So what happens to all the information? We work closely with National Park ecology team and Forestry Commission. The information we provide will assist in decision-making processes regarding management of the Forest.
One of three Barbastelle roost sites identified Barbastelle female
I estimate the survey will take up to 3 years. If you are interested please come along to any of the training events or talks which will be posted in Bat Droppings and/or on this website. Training will be for committed volunteers in surveying and radio tracking (free of charge) and there will be an afternoon talk at the museum in Lyndhurst (cost £4). We will circulate details of the training course at least a month or 6 weeks in advance to all members so please look out and come along!
Colleen Mainstone & Paul Hope
Serotine Survey
In 2003 we reviewed the number of Serotine maternity roosts in Hampshire - most of which were in buildings (in line with the ecology of this species in the UK). The survey involved counting bats out of houses on 2 nights during June/July. As this type of survey causes no disturbance to the bats a licence was not therefore required. We had over 85 records of Serotine sites built up since 1985. As Serotines are highly nomadic we estimate that perhaps only 10 - 15 were probably maternity roosts. Hampshire Bat Group wrote the latest Biodiversity Action Plan for Serotines in 2003 and ongoing survey work forms an important part of the outcomes of this plan, which will eventually better inform us of the significance of Hampshire for this southern species and enable us to monitor its population in future years.
This survey depends upon continued enthusiasm as roosts require constant monitoring. Serotines are a relatively easy bat for the novice to learn to detect on a bat detector and even visually – being a big bat that flies along woodland edges and over pastures and wetland areas. Any large bat is of interest! We currently have a number of areas in Hampshire where we would like people to look out for this species and trace roosts which we know are to be found locally. This includes Alresford, Privett, Bishops Waltham, Netley, Southampton (Common area), Sherfield English and north Hampshire!
Contact Colleen if you can help.
Romsey and Lower Test Valley survey
This was a project to find and assess roosts and identify key feeding areas in Romsey and the Lower Test Valley. This area covers Stockbridge south to Rownhams, eastwards to Sherfield English / West Dean and westwards as far as Chilworth and North Baddelsy. Help is required counting bats out of houses during the summer and surveying important feeding areas. Over 70 potential roosts were identified in 2002 and a number of roosts subsequently. Contact us if you know of any more roosts in the area.
Greywell Tunnel
Contact Paul Hope direct for more information on this project.
Hibernation Counts
During the winter bat group members are active undertaking regular surveys of hibernation sites such as disused railway tunnels, old pill boxes, historic buildings and ruins and many fortifications along our coast and a purpose built bat cave near Eastleigh! Numbers are limited to reduce disturbance as many of these sites are sensitive, however opportunities are available for new people training for a licence or just wanting relevant experience.
National Projects
National Bat Monitoring Project
Surveyors are always needed to support BCT (Bat Conservation Trust's) national bat monitoring projects (NBMP). A number of different species are organised by Bat Conservation Trust each year. Specific projects for monitoring Daubenton's on rivers, Noctules, Serotines and Pipistrelles (NSP) on walk about transects, counting Serotines, Daubenton's and Natterers from roosts. For more information visit BCT's website. Many of the NBMP surveys tie in well with local surveys and information can be shared. Hampshire Bat Group can help you by providing training or information on householders willing for people to count out their bats and possibly with relevant equipment. Please ensure that any data you collate is given to the Hampshire Bat Group as well as BCT EACH YEAR!
Bats and Roadside Mammals Survey
This joint project between Bat Conservation (BCT) and Mammals Trust UK (MTUK) began in 2005, building on from a MTUK survey running since 2001. The survey entails driving slowly down a transect route recording bats using a time expansion bat detector and taking notes of mammals alongside the road. The Hampshire Bat Group was one of several bat groups who took part last year, and will continue the survey this year, beginning in May. For more details of this survey or for how to take part see page 7 of the Spring edition of “Bat Droppings” or contact Hampshire survey organiser Erika Dahlberg on 01962 849216.
Other Previous Surveys
These have included the following investigations:
Itchen River Survey
This project was undertaken ion conjunction with the Hampshire and Isle of Wight Wildlife Trust and the Environment Agency. The aim was to survey bat activity around the river Itchen and its catchment from Southampton to just north of Eastleigh. Information gleaned from this work informed management advice and a new leaflet for landowners of the riparian landholdings.
Mottisfont Survey
Over the period of 2000 and 200, more than 60 dwellings on National Trust land at Mottisfont were surveyed by bat group members. Subsequent surveys revealed the significance of surrounding woodland for a wide number of species including the rare Barbastelle bat. Roost were located for Natterer's bat, and Noctule, Common and Soprano Pipistrelle, Serotine and Whiskered/Brandt’s bats have also been recorded.
