Mammals of the British Isles handbook, 4th Edition

"This is a wonderful tome. It’s a big book. It’s not the sort of thing you’d read on the beach or put in your handbag. It’s a monster book. It’s massive. It’s in its fourth edition now and has been coming out for 30 years. It’s a collection of all the mammals we know in the UK. It’s written not just by professionals but also by amateur naturalists who have been looking at a particular species for many years, sometimes all their lives. It’s a tremendous insight into the mammals we have here. It’s really based around the work of the Mammal Society which assembles the knowledge of all these mammalogists together. Bat-wise it’s tremendous because a quarter of all the mammals in the UK are, in fact, bats. Yes. And it’s got all of them outlined in lovely detail and with such great insight because some people who study bats don’t just study bats, they study one species of bat and their whole life is spent looking at that one species. Every aspect of their life is covered. I’ve been looking at Daubenton’s bat. It’s known as the water bat, as it’s a specialist feeder of aquatic insects and it skims across the surface of still water, lakes, reservoirs and so on, snapping up the insects off the surface with its very large back feet. I’ve found out where these bats fly to, how far they can travel, what a group of these bats does, and how each individual is related to another. They usually live in hollows of trees overhanging or near to water. We’ve been tracking them now in my home area for 20 or 30 years or so and we put little rings on them so we can see individuals and see how far they travel. They can go ten kilometres or more from the roost to a foraging area and they are travelling for a reason. Gilbert White was trying to get his head round this too. Why do they go so far when there’s apparently better feeding round where they live? I think they’ve got a very complex social structure, so they don’t live just in one little community. There are a number of communities that they go to over the period of a year or so, so they’re constantly moving between these communities, checking up on each other. It’s not just males/females meeting up, it’s also males and other males, females and other females, so there are roosts that are constantly changing depending on who’s present, like a series of hotels across the landscape. The individuals in the hotels change every night. That’s a very difficult question because the roost changes nightly, so one night a roost might have five bats in it and another night it might have 50. Just like a hotel – weekends it’s very busy. Having put a marker on the bat we have found that sometimes we might not see it again for 12 years until it comes back to that particular roost. 20 or 30 years. The longest-lived record is of a Brandt’s bat, a small insectivore bat, that was found in Russia when 41 years old."