Where bats are present in a structure flight surveys are an essential component for
the reports which form part of a planning application. Once planning is granted they
also form the basis on which an ‘EPS’ Licence application is made to Natural England.
It is therefore very important that the survey is performed in such a way that sufficient
results are obtained to allow both the planning process to proceed and subsequently
a Licence to be applied for.
What is a Flight Survey
Emergence surveys are conducted from before sunset until sometime after sunset using
a number of our fully licensed surveyors with bat detection equipment. For building
surveys the number of surveyors will depend on the footprint of the building and
sight lines of the roof scape. The detection equipment brings the ultra sound vocalisations
made by the bats to a level which can be heard and from these the species can be
Throughout the survey session each surveyor will record the output from the detectors
on a digital recorder so that it can be analysed later with sonogram software to
check species identification and timings of the bat sightings. During the survey
the surveyors are coordinated working to synchronised stopwatches and in radio communication.
This allows the notes made by individual surveyors to be compiled later to form a
master plan of the bat activity. To supplement the surveyors we also deploy a number
of infra red CCTV cameras together with high power infra red floodlighting. Images
from the cameras are recorded on commercial CCTV digital recording equipment which
is working to the same time base as the surveyors. Because the cameras are synchronised
the recordings can later be viewed to provide accurate counts of individuals identified.