A very overdue update on the Bat Saga. The last time I wrote we had identified that bats had been using the attic at the house for a roost. We therefore had to arrange a full bat survey. This involves a team of ecologists undertaking three surveys over a six week period; two of these are dusk surveys taking place from 30 minutes before sunset till 3 hours after and one is a dawn survey taking place 2 hours before sunrise and half an hour after. The surveys cannot start before May and they have to be completed by September so there is a very small time window in which these can be done. Particularly given that the surveys cannot be done in the rain.
Each week before the survey saw me watching the weather forecasts keeping everything crossed that the weather would be fine. If a survey is cancelled due to bad weather you may have to wait a few weeks for another one as ecologists are heavily booked in the survey season.
We were incredibly fortunate with the weather for our three surveys. It did start to rain during the first dusk survey but as the bat watchers were able to observe for over an hour before the rain started we were told it counted as a “credible survey”, however this meant that the other two surveys would have to be undisturbed by the weather. The second survey passed off without incident, the third survey was fine and dry until about 2300 hours and then a storm came, but taking sympathy on us the team decided they had seen enough to be satisfied that they knew how and where the bats were roosting on the property and they signed the survey off.
Mark and I joined the team for the final dusk survey which was both informative and fun. The ecologists use a device attached to a tablet which picks up the sonar signals from the Bats and from this can determine what species of bat it is. I was lucky enough to see a Pipistrelle bat catch an insect and the moment of it catching its prey was clear from the spike on the tablet.
We also learnt some interesting facts about bats such as they can eat up to 3000 small insects in a night; the phrase “blind as a bat” only in fact applies to cave dwelling species, the more common bats we saw are not blind and use their sight to navigate; their sonar is used for hunting prey and some insects have adapted to detect the sonar signal of bats and take evasive action such as folding up their wings and diving. Bats use hedgerows and streams as navigation pathways as these have a density of insects. Bats tend not to fly when its raining, not because they don’t like the wet but because there will be no insects to catch!
Over the course of the three surveys the bat watchers observed brown long-eared Bats and Serotin Bats flying around the area but none entering or leaving the building. The only bats they observed actually entering the roof were the Pipistrelles, that roost in gaps under the roof tiles. These were seen emerging from and entering two areas of the roof.
The bat license application was duly submitted to Natural England and at the end of June we received the license. This allows us to remove the roof under supervision by an ecologist. I have purchased two bat boxes which will be fixed to a tree by the stream and any bats found will be placed in these. I hope to be able to be there on the day the ecologist removes the bats so watch this space for actual video footage of the event.
We will also have to construct a permanent roost above the car port – it will however be three to four years before any bats will use this new roost – or to plagiarise an old proverb “Before our bats come home to roost!!”.