The Harvest Mouse
1 Discovery and Context
2 Micromys - Description
3 That Wonderful Procreant Cradle
4 Where Are They Now?
5 Deaths and Entrances
6 Keeping Harvest Mice as Pets
Considering the number of naturalists out and about in the British countryside, making observations on the butterflies, dragonflies, birds and moths and snakes and lizards (but mostly the birds it has to be said), the mammals, given their size and known distribution, are surprisingly poorly watched and studied.
And the simple reason for this is that they are secretive and the most secretive of them all must be the Harvest Mouse – at least among the rodents.
Anyone wandering about or resident in the British countryside for a number of years will have seen Hares (including Mountain Hares in the right places) Rabbits, Stoats and Weasels, heard shrews, will remember Water Voles, glimpsed Field Voles, watched deer, been pestered by Wood and House mice and been disgusted (or captivated) by Brown Rats. You don’t even have to leave home to see Foxes though unless you’re lucky a special excursion is usually necessary to watch live Badgers for a prolonged period; dead ones, as roadside casualties, are unavoidable over much of Britain.
Others remain elusive; lowland Otters have a deserved reputation for being inconspicuous, as do Polecats and Pine Martens and especially Wild Cats but these are quite rare and rather sparsely distributed.
Not so, the Harvest Mouse. In some years they can be quite abundant. They are resident over much of England, especially south and east of the Bristol – Humber line and they occur in many kinds of habitat. If you have followed a few public footpaths in the southern half of England, you will have loomed large on many a Harvest Mouse’s horizon. But you almost certainly won’t have seen one, or even had the slightest notion that they were present. After a lifetime’s interest in all things natural and twelve years keen interest in Harvest Mice, I gained a chance sighting of one in the wild during the preparation of this website: my keen-eyed daughter spotted a juvenile on the edge of dense grassy-scrub on a walk in August 2011.
Harvest Mice have a tremendous advantage over Otters when it comes to keeping incognito; their size. That is to say, their lack of it. Their scientific name, Micromys minutus means “smallest, tiny mouse” and even when you have prepared yourself for how small they are going to be, seeing one for the first time is still an endearing surprise. They weigh about the same as a twenty-pence coin and they are just a little longer than a thumb – including tail. So, given that a favoured summer habitat is rank grassland growing up through bramble and that in some years they can be mighty scarce, I think that searching for a Harvest Mouse in a hay meadow is akin to looking for a needle in a haystack (though, ironically, there is more point to it).
In contrast, it was at one time a very easy exercise to spot a Harvest Mouse in a hayrick; Gilbert White was a pioneering naturalist who lived at Selborne in Hampshire nearly all his life. In his time, the eighteenth century, Harvest Mice were abundant in the ricks that were brought in to the farm-yards in the late summer which is when they were brought to the great naturalist’s attention.
It was based on White’s own observations and measurements of these mice, which he compared to those in the available works of the day, especially those by Ray, and through his correspondence with Thomas Pennant, that he realised these mice were “non-descript”; that they had not been described before.(Discovering a new species to science was not a unique experience for this keen observer; he also realised that Willow Warblers, Wood Warblers and Chiffchaffs were indeed three species and not the one that had hitherto been thought).
In 1767, Gilbert White communicated his discovery to Pennant who published information on the new species of rodent in the 1776 edition of his British Zoology. The entry ran to 207 words and was a pure digest of White’s letters. It is no surprise that Pennant was unable to add further to Gilbert White’s thorough observations in the few years that elapsed since the letters of 1767 and 1768 but in 1952, the Collins New Naturalist volume on British Mammals (No 21 in the series) by L. Harrison Matthews could still only muster fifty two lines of text in the main entry for the species, much of which was based on White’s notes or speculation: Dr Matthews did however begin the entry with the words; “On the little harvest-mouse, Micromys minutus soricinus, no modern research has been done.”
Some years later, Dr Matthews asked for the volume to go out of print as he “could not let readers be fobbed off with so out-of-date a book”. Such a large amount of information had come to hand that it was agreed he should write a sequel but a reader might conclude from the resulting volume, “Mammals in the British Isles” first published in 1982 that this new information did not relate to Harvest Mice as the later volume contains just thirty lines on the species!
Which is odd since it was in the late 1970’s that our knowledge of Harvest Mice improved. The improvement was substantial and was led by a young doctor who had gained his PhD studying the ecology of foxes. It manifested itself, in popular format as the book The Secret Life of the Harvest Mouse by Stephen Harris in conjunction with Oxford Scientific Films and was published by Hamlyn in 1979. Dr Harris also wrote The Harvest Mouse, published by Blandford Press in 1980. Both books are out of print, but second-hand copies, sometimes in good condition can be sourced through the internet. The 1979 book accompanied a half-hour film in the popular Survival series of natural history films called Small is Beautiful which was transmitted on ITV on 7th September 1980.
Much of the biology and ecology of the Harvest Mouse on this site is drawn from these earlier works and from the relevant entry in Mammals in the British Isles: Handbook 4th Edn published by the Mammal Society and edited by Dr Harris and Dr Derek Yalden.