The project objectives are fourfold and married with their definitions of success as follows: –



Objective: The identification and description of all features exploited by specific tree-roosting bat species native to the British Isles.

How the objective will be achieved: The comprehensive identification of PRF will be achieved by eliciting PRF records with accompanying photographic accounts. Where records of features not already identified and described are submitted, the recorder will be debriefed to ensure a full and accurate description is recorded.

Definition of success: In October 2028, Bat Roosts in Trees will have been available for a decade. At this point we will assume the list of Potential Roost Features identified to that date are exhaustive save for anomalous situations.



Objective: The identification of the mechanisms by which all features exploited by specific tree-roosting bat species native to the British Isles come into being.

How the objective will be achieved: What we think is the full complement of PRF was set out in the 3rd Edition of the Bat Tree Habitat Key in 2016. In October 2018 the first edition of Bat Roosts in Trees was published. Arboriculturalists and ecologists will be publicly encouraged to provide evidence-supported criticism of the PRF accounts therein, and to contribute to the understanding of any new PRFs subsequently discovered.

Definition of success: a scientifically robust description that is accepted as accurate by the Arboricultural Association and BTHK.



Objective: The identification of the biological and environmental attributes that will inform an analysis framework in ‘app’ form, through which field data may be processed to immediately give a % probability that a specific PRF is suitable for a specific bat species, for a specific purpose, in a specific period of the annual cycle.

How the objective will be achieved: a) provision of an online database that can be contributed to by anyone and is of practical use to everyone; b) collection of ad hoc records of features that are known to be exploited by bats on dates when the bats are present and when they are absent, as well as PRF that are not known to be roosts; encouragement for recorders to make repeat records at fixed intervals (i.e. monthly etc.); c) collation, truthing and analysis of close-inspection data in records submitted to the BTHK Database; d) the definition of an analysis framework; and, e) the commission of an app-designer to create the app.

Definition of success: A free online app that is available for the widest range of handheld mobile devices.



Objective: The definition of a tree-roost finding strategy for each individual bat species that can be proven to work with empirical evidence.

How the objective will be achieved: The achievement of Objectives 1, 2 and 3 will broadly inform the detectability of the roost features typically exploited by individual bat species. However, it will be necessary to truth this assumption by visiting known roosts that have been discovered by radio-tracking during the winter months, and assessing whether or not they are visible from the ground. This will therefore inform which individual method is likely to be effective in discovering specific PRF types that are exploited by specific bat species in each period of the year.

Definition of success: The marriage of specific tree-roost finding methods, with specific bat species, in specific periods of the year with an empirical measure of confidence in their efficacy.