ATLAS OF THE MAMMALS OF GREAT BRITAIN AND NORTHERN IRELAND
Derek Crawley et al & The Mammal Society (Eds)
Pelagic Publishing, 2020, 204 pages
Hardback £35 ISBN: 978 1784 272 043
Review by Ian Bond
Producing an Atlas ought to be one of those things your mother warns you against. They are so much work, they take so long and the minute you finish them they are out of date. And as for picking a cryptic, principally nocturnal taxon like mammals, well why would you? I’m glad somebody did though as this is well overdue.
The previous Atlas of mammals in Britain is almost 30 years old now and its “recent” category includes records up to 30 years older than that. It was based on what was an impressive 115,000 records but even so had some notable limitations, for example showing the north of England as a Daubenton’s bat free zone. The current Atlas increases that recording effort 15 fold and consequently reflects what we now know about Daubenton’s bat presence on almost every significant watercourse.
With almost two million records there is bound to be one or two dodgy ones in there and no more so than with bats. I was amused to see a comment on social media by the author of one of the Atlas’ bat species accounts to the effect that half the bat records in Scotland are fiction. No doubt he meant it as hyperbole but I share his frustration; there is an increasing army of bat disciples whose faith in the bat detector is perhaps a little too fundamentalist. One record that jumped out at me as being particularly out of place was a Serotine in Hartlepool for the period 2000-2016. I was the local authority ecologist for Hartlepool for almost that entire period and I also researched and wrote the chapter on Vagrant Bats, for the North East mammal atlas. If I ever appear on Mastermind, my specialist subject will be “Rare bats in Hartlepool, 2000-2016” and I’m not expecting a question on Serotine. Inevitably there will be some other minor limitations. As the Atlas itself points out there may be discrepancies between the Atlas maps and the known distribution as not everything is submitted as a record, which no doubt explains the apparent demise of several mammals including the brown rat on the Channel Islands after 1992. It also stresses that a positive hectad represents a record and not a population; an important consideration for highly mobile species such as bats and deer which can (and do) generate records well away from their usual distribution.
Nevertheless these are minor points, what counts is the resolution provided by the sheer number of records and even more important the ability to look at changes in distribution over time. The change in range is, as expected, illustrated with symbols on the maps but the change in the number of records and the change in the number of hectads are also handily tabulated. That the red squirrel is down by 387 hectads is no surprise but that it is pipped for first (or last?) place by the house mouse on minus 388 perhaps is.
The Atlas covers all 60 resident species of terrestrial mammal plus all 30 cetacean species which have been recorded as a live sighting in British and Irish waters. Each of these has a double spread with a full page distribution map and graph showing the seasonality of records, accompanied by around 300 words of text under the headings, distribution, ecology and identification, along with a selected bibliography and an illustrative photograph to encourage further recording. As someone with a particular interest in mammals I initially dismissed the text as ‘fairly basic stuff that I probably knew already’ but on reflection this actually makes an excellent handbook of British mammals for the non-specialist. I tested this on myself with the cetaceans, which I have previously taken little interest in, leaving them to people with more patience and better sea legs: it’s just the job! In fact given that it is also a delightful book to look at, I think they should also market it as an introductory handbook, rather than just targeting the more niche market of atlas afficianados.
Atlases are just sticks poking up in the sands of time, but mammal populations are still changing, in some cases rapidly. For water vole the “current” category was brought forward to 2005-2016 to try and accommodate this and its wholesale loss across North Yorkshire and Cornwall leaps out of the page. Even so there are way too many presence dots to reflect its distribution as of 2020. So, I hope it’s not another 30 years before someone else is brave enough to marshal an update. If they do then this Atlas will stand out as a clear mark in the sand to compare with.