This study explores whether Natterer's bats exhibit fidelity to their foraging sites and individual specialization in their use of habitat types. The research tracked 34 individual bats in two different landscapes, with some bats tracked twice over varying time intervals. The study found that Natterer's bats show consistency in their fidelity to foraging sites across different landscapes and intervals between observations. The bats repeatedly exploited specific foraging areas, and some showed individual specialization in their habitat use. The study also found considerable variation in individual behaviour. The research suggests that a single full night of radio-tracking data can serve as a useful proxy for longer periods and contribute to more robust descriptions of resource requirements by Natterer's bats in their breeding seasons. This study emphasizes the importance of maximizing the number of individuals from which movement data is obtained to inform conservation and management of temperate bats, while ensuring that the data represent a meaningful measure of behaviour. The results also suggest that protecting a mosaic of habitats rather than a single habitat may be important for Natterer's bats, given their individual specialization in habitat use.

There have been significant declines in population numbers of many bat species in the United Kingdom, including Natterer’s bats Myotis nattereri, over the last century, largely due to anthropogenic changes. The philopatry, which temperate-zone bats often exhibit to their natal landscapes, in combination with anthropogenic threats, can lead to fragmentation, isolation and sub-division of populations. This may result in bottlenecks and declines in genetic diversity. Multi-scaled research is required to disentangle how the variation in the physical traits of bat species (e.g. affecting flight), as well as their social and behavioural traits (e.g. community size, migration, breeding systems), may affect the genetic health of populations and provide a potential buffer against fragmentation. We used microsatellite markers to characterise the genetic diversity and population structure present in Natterer’s bat colonies to determine whether summer roosting bat colonies were spatially differentiated or part of a meta-population. Analyses of population structure and measures of genetic relatedness suggest spatially differentiated populations of bats exhibit long term site fidelity to summer roosting sites, whilst high genetic diversity at sites indicates gene exchange occurs via swarming sites. Natterer’s bats in northern England may travel greater distances to swarming sites than has been previously documented.

101. Bat populations have declined globally over the last century largely due to 11 anthropogenic change. Many temperate forest species of bat appear loyal to their 12 foraging sites however, conservation of these sites rather than just habitat types is 13 rarely considered and is essential to protect bat populations. It is not clear whether 14 site fidelity in bats is species-specific or a more general trait or why it is exhibited but 15 behaviour patterns could be important for conservation and management 16 objectives. Foraging variation may occur due to 'individual specialisation', such that 17 individuals differ significantly in their prey or habitat utilisation, independent of 18 class-effects. If bats do exhibit individuality in their habitat choice, then protection of 42 Introduction 43 Globally bat populations have declined considerably over the last century largely due to 44 habitat loss, hunting, or disease (1) with recovery predicted to be slow (2). Determining 45 habitat types required for effective conservation of bats can be difficult compared to 46 terrestrial mammals of similar size, due to their ability to fly, which enables them to travel 47 long distances, allowing use of a wide range of resources across a wider variety of habitats.48 In summer bat roosts and foraging sites can be kilometres apart permitting them to 49 assemble widely dispersed resources they require for survival and reproduction from across 50 extensive landscapes (3).51 Flight and the large areas it allows bats to exploit, can also expose individuals to a range of 52 anthropogenic threats such as development (inc. residential, commercial and infrastructure) 53 or sources of mortality such as wind-turbines (4-9) and roads (10-13) on a nightly basis.54 These threats can also affect roosts, reduce or degrade available foraging habitat or 55 interfere with the connectivity between habitats (1). Although the conservation of roost 56 sites is important for the maintenance of bat populations e.g. (14), roost provision or the 57 mitigation of roost loss is already common in the management of bat populations. In 58 addition to this, many species use a network of alternative roosts and cope with the loss of a 59 few (15-18) . Conversely, bats appear loyal to their foraging sites despite roost loss (17).60 Hence, the conservation of foraging sites (rather than just habitats) may be as important as 61 roost sites in the conservation of the species, although rarely considered. Further, it is not 62 clear that there are tools to confidently identify the most important foraging areas in the 63 landscape (rather than particular preferred habitat types). This is of some concern especially 64 as determining priorities for policy led management of habitats requires a robust 65 understanding.66 It is not clear whether site fidelity in bats (14, 19) is specific to temperate forest bats, a more 67 general behaviour found in other species or why it is exhibited. Initial work by Egert-Berg et 68 al (20), suggests that many bats may demonstrate a su...