Case Studies
Kingston Lodge, Manchester
Background
In May of 2020 a diurnal bats and breeding birds inspection was undertaken
at Kingston Lodge (Figure 1), a detached two-storey Victorian cottage featuring
a cellar located in Didsbury, Greater Manchester, which revealed the presence
of 30-40 droppings in the loft void of the building alongside feeding remains –
indicating use of the space as a roost. A further 30-40 Brown Long-eared bat
droppings were found in the cellar, suggesting the building may also be being
used for hibernation; as a result, the building was categorised as pertaining to
‘High’ bat roost suitability in line with BCT guidance.
Between July 2020 and August 2020 two dusk surveys and one dawn survey
were conducted to confirm the presence of a bat roost(s), establish species
present and their abundance. From these surveys it was learned that Kingston
Lodge was being used by one Brown Long-eared maternity colony as a satellite
roost; utilising the loft space with numerous emergence and re-entry points
observed. Additionally, a further single common pipistrelle day roost was
identified at the building.
It was proposed that Kingston Lodge would be renovated, and an extension would be added to the southeast corner of the building thus meaning that the retention of the identified roost features in their entirety would not be feasible, thus, alternative roost mitigation provisions would need to be provided following the granting of a Natural England licence.
Mitigation
Works were undertaken during the hibernation season for bats (September – April); therefore, as Kingston Lodge held hibernation potential, prior to any works occurring at Kingston Lodge a permanent hibernation box (see Figures 2a-2b) was installed under tree canopy to compensate for the loss of potential hibernation opportunities in the cellar and provides a safe alternative location for hibernation. This bat box will be retained for the foreseeable future so that it will providing roosting opportunities for bats all year round.
Within Kingston Lodge, a dedicated permanent bat loft (Figure 3) has been created within the apex of the building to provide like-for-like roost provisions for bats utilising the loft void; this bat loft is to the same dimensions and aspect as the previously existing loft space. The bat loft is constructed of Timber retained from the pre-existing loft to further mimic the previous conditions of the pre-existing loft space.
The dedicated bat loft can be accessed via two bat access slates, located at northern and
eastern elevations – an example of which is provided in Figure 4. To increase accessibility
further and enhance the value of the building for bats even more, ridge access provisions
were also incorporated into the mitigation designs. In addition to the bat loft, two
integrated bat boxes were installed, also at the northern and eastern elevations.
Monitoring
In 2021 a static bat detector was installed in the loft from May to June as the first stage of
monitoring the success of the mitigation.
This case study will be updated with results of the monitoring presently.
Figure 1: Kingston Lodge prior to renovation
Figure 2a & 2b: Permanent bat box installed on a tree at the southeast of the site
Figure 3: Illustration of the location of the dedicated bat loft
Figure 4: Example of bat access tile used at Kingston Lodge
Mere Sands Wood Tower Hide
Background
Mere Sands Wood is a Lancashire Wildlife Trust (LWT) reserve and is also
designated as a Site of Special Scientific Interest (SSSI). Within the wood is a
'tower hide' (Figure 1) which was historically used for bird-watching, but has
been closed to the public for a number of years due to its deteriorating
condition which has rendered it unsafe. As a result, LWT decided to dismantle
the hide in 2022.
However, four bat boxes of two different designs had been mounted beneath
the hide for a number of years (see Figure 2); previous surveys of these bat
boxes by Merseyside and West Lancashire Bat Group (MWLBG) had indicated
that the boxes were actively used by up to three species of bat in a variety of
roost types, in both the summer and the winter.
Given its poor condition, the demolition of the Tower Hide was considered
necessary, but this would also have a negative impact on the confirmed bat
roosts.
Surveys
Therefore, in May-June 2022, Tyrer undertook dusk/dawn surveys in order to supplement existing knowledge of how the bat boxes and tower hide were being used by bats. Based on the previous data at the hide, the structure was categorised as pertaining to
‘High’ bat roost suitability, and therefore three activity surveys (two emergence dusk and one dawn re-entry) were undertaken.
From these surveys it was ascertained that the interior of the Tower Hide and
it's bat boxes were being utilised by a maternity roost of brown long-eared
bats as a satellite roost, alongside day roosts of both Daubenton’s and
common pipistrelle bats. Furthermore, it was learnt that the underside canopy
of the hide was used for brown long-eared bat swarming, resting and
interaction post-dusk emergence and pre-dawn re-entry.
Clearly the presence of the canopy played an important role during the
breeding season and to a great extent mimicked the actions of brown
long-eared bats when loft spaces are their chosen roost. Swarming behaviour is
mainly associated with autumn/winter hibernation sites and dawn re-entry at
summer roosts; the extent of this behaviour is not fully understood but the
general hypothesis is that during autumn it may be related to mating activity
whilst in summer it is social interaction.
In addition, historic survey data from MWLBG had previously confirmed that a
roost of brown long-eared bats had occasionally but not consistently utilised
one of the Tower Hide bat boxes for hibernation, with another occasionally
used by a common pipistrelle bat for hibernation.
Evidently, the demolition of the Tower Hide would result in the loss of a number of bat roosts alongside a swarming site, and hence the full demolition of the hide would need to be re-considered, alongside the provision of alternative new roost mitigation provisions following the granting of a Natural England licence.
Overview of Mitigation
Once a Natural England Licence was in place, works were undertaken in November-December 2022, after the summer active season of bats had finished; these works were all undertaken under the supervision of an Ecological Clerk of Works (ECoW), to ensure that no negative impacts to roosting bats occurred.
Prior to works commencing, each of the bat boxes beneath the Tower Hide was temporarily removed and relocated to nearby trees, to avoid any potential disturbance. Then, in order to make the Tower Hide safe and stable, the hide, canopy and staircase were removed, only leaving the floor and support posts which were retained. This removed the potential for anyone to enter the hide, simply leaving a standalone platform structure that could be used for roosting bats.
A dedicated, permanent bat loft (see Figure 3) was then created on the platform, with the same dimensions and aspect as the former interior of the Tower Hide to mimic the previous conditions of the hide and thus retain roosting opportunities for the bats previously utilising the interior. The exterior of this loft was also to be coated in timber cladding, providing further crevice opportunities that could be utilised by other bats (Figure 4).
Following these works, the bat boxes that had been temporarily relocated were then reinstated on the support beams of the tower hide.
These mitigation measures ensured that the Tower Hide could be partially demolished, removing any potential negative impacts to the general public, while also retaining all of the existing bat roosts, and enhancing the structure to encourage more bats to utilise the structure in the future. See Figure 5 for the character of the Tower Hide as of January 2024.
Monitoring
Monitoring of the tower hide and its bat boxes was proposed for January and February of 2023, 2024 and 2025 to assess the use of the structure in a hibernation capacity, alongside June and August of 2023, 2024 and 2025 to assess its usage in a day, maternity or satellite capacity.
Early results of this monitoring have shown that the bat boxes continue to be utilised by brown long-eared bats, indicating that the mitigation measures have provisionally been successful at the tower hide.
At the time of writing, the most recent monitoring survey was undertaken in May 2024.
A total of ten brown long-eared bats were recorded emerging from a Greenwood's Ecohabitats bat box, erected as a part of the EPSML measures at Mere Sands tower hide. The bats emerged between 21.40 - 22.03hrs, and foraged briefly around the box before commuting into the adjacent broad-leaved woodland. A Batlogger M2 and Nightfox Whisker were used to record bat activity following an endoscopic investigation confirming presence. In addition to the brown long-eared bats, also recorded by the surveyors were common pipistrelle, soprano pipistrelle and whiskered / Brandt's bats.
Figure 1: The tower hide at Mere Sands Wood prior to works in 2022
Figure 3: Illustration of the dedicated bat loft specification created at the tower hide
Figure 2: Bat boxes mounted beneath the tower hide prior to works
Figure 5: Character of the tower hide following provision
Figure 4: Illustration of the proposed character of the tower hide following works