Past and present status of the Yellow-necked Mouse

PAST AND PRESENT STATUS OF THE YELLOW-NECKED MOUSE

J. R. MARTIN The Yellow-necked Mouse (Apodemus flavicollis) is one of four species of mice which live in the British Isles. Althougli it is very similar in appearance to the Wood, or Long-tailed Field Mouse (Apodemus sylvaticus), it can be distinguished from that species by the presence of a band of yellow für on the upper ehest which stretches from Shoulder to Shoulder. On some animals the band may be quite pronounced, whilst on others it may not be so bold. Even so, the band is still discernable, even on juveniles. The Wood Mouse usually has a small patch of yellow on its ehest which, on some animals, may be quite large. However, the patch never reaches the shoulders as in the Yellownecked Mouse (Fig. 1). The Yellow-necked Mouse may also be identified by its brighter more orangey brown für and its paler ventral colours. This gives the animal a bright, sharp and attractive appearance. The Wood Mouse has a darker brown upper surface, and the under für is greyer.

Large ears and eyes identify both species as predominantly creatures of the

Apodemus flavicollis

Apodemus sylvaticus (.COLI

7.

Top: Yellow-necked mouse Below: Wood mouse

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night, although the Long-tailed Field Mouse may s o m e t i m e s be f o u n d during daylight h o u r s in the s u m m e r . C r a n b r o o k (1968) r e p o r t e d an instance of his dog catching a Yellow-necked Mouse during daylight, but such sightings a p p e a r to be rare.

T h e o t h e r two species of mice which are f o u n d in Britain, t h e Harvest M o u s e (Micromys minutus) and the H o u s e M o u s e ( M u s domesticus) d o not have the yellow ehest marking and can easily b e distinguished f r o m A. flavicollis and A. sylvaticus using o t h e r characteristics (see C o r b e t & Harris, 1991 for example).

A p a r t f r o m these f e a t u r e s the Yellow-necked is also a m o r e robust c r e a t u r e than the W o o d M o u s e , and a fĂźll grown male may m e a s u r e b e t w e e n 9 5 - 1 2 0 m m , excluding the tail which may m e a s u r e an additional 9 8 - 1 1 3 m m .

T h e W o o d Mouse may m e a s u r e b e t w e e n 8 8 - 1 0 0 m m , and its tail m a y measure an additional 8 4 - 1 0 1 m m . A l t h o u g h all small m a m m a l s can b e lively and difficult to handle, the Yellow-necked M o u s e can be especially difficult in this respect; it also tends to bite m o r e readily. T h e s e two characteristics can be clues to its identification, b e f o r e a m o r e critical e x a m i n a t i o n in the h a n d . T h e Yellow-necked M o u s e can also be very vocal, and t o t h e uninitiated mammalogist this can be unnerving when handling it for t h e first time.

It can leap considerable distances, and o n e which I live-trapped in my garage leapt a distance of 4ft. f r o m my hand and clung to a brick wall.

Status, Distribution and Habitat T h e Yellow-necked M o u s e is f o u n d in many parts of E u r o p e , although it is absent f r o m much of Fenno-Scandia, southern F r a n c e , Italy and Spain. In the British Isles it is absent f r o m Ireland and is confined to t h e s o u t h e r n parts of the mainland. In East Anglia (i.e. Essex, N o r f o l k , C a m b s . & Suffolk) its distribution is irregulär. For e x a m p l e , it is thinly distributed in S u f f o l k and Essex. In Essex its status has been described a s ' f a i r l y stabil ( H u g h e s , 1986).

In C a m b r i d g e s h i r e it is a comparatively rare animal, and in N o r f o l k it has been described as 'tantalisingly elusive' ( H a n c y , 1992). A t t h e ' M a m m a l M a n i a ' wildlife c o n f e r e n c e held in Ipswich on 30th O c t o b e r 1992, J o h n Flowerdew suggested the status of t h e Yellow-necked M o u s e in Britain might be worthy of monitoring.

Various reasons have been put f o r w a r d for the patchy distribution of this species. M o n t g o m e r y (in C o r b e t & Harris, 1991) suggested a p r e f e r e n c e f o r long-established w o o d l a n d in drier a r e a s of Britain, and recently Y a l d e n (1992) considered its distribution closely fitted that of the ' A n c i e n t C o u n tryside' which R a c k h a m (1986) p r o p o s e d . It d o e s s e e m that t h e Yellownecked M o u s e is m o r e usually associated with w o o d l a n d and h e d g e r o w s f o r , unlike t h e W o o d M o u s e , it is not usually f o u n d on o p e n a r a b l e fields.

H o w e v e r , C r a n b r o o k (1968) r e p o r t e d an instance of a Yellow-necked M o u s e being f o u n d in a field 30 yds. f r o m a b o u n d a r y h e d g e . H e stated that in his experience it was u n k n o w n for a Yellow-necked M o u s e to be f o u n d in that type of h a b i t a t .

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History of the Yellow-necked Mouse in Suffolk It was not until March 1903 that the Yellow-necked Mouse was first described from Suffolk ( R o p e , 1911), when an adult female was captured at Tostock by the Rev. Tuck. H e presented it to R o p e , who in turn presented it to Norwich Museum. In the following month, on 18th April, Tuck sent a n o t h e r f e m a l e to Norwich M u s e u m , and on 18th June he sent two more specimens which had been caught by his cat. Why some or all of these specimens were not presented to any of the Suffolk museums is a mystery.

It was not until 1937 that this species was once again reported f r o m Suffolk when two were caught at Higham. These were subsequently sent to the late Lord C r a n b r o o k . It was also reported at that time that the British Museum of Natural History was in possesion of a male f r o m Woolpit (Andrews, 1937).

Although there were a few more records from various parts of the County (namely Troston, Thorndon and Mendlesham) during the 1930s, little eise was reported on this species until 1952, when the late Lord Cranbrook reported ( C r a n b r o o k , 1952) 'Little is known ofthe distribution ofthis animal in the county though it has been reported from a number of places' (Woodbridge 1949, Fiatford 1951, Dunwich and Newbourne 1952).

From 1952 until the early 1970s the Yellow-necked Mouse was regularly recorded, although it was by no means common. It was during this period of heightened activity that Lord Cranbrooke remarked on its status in Britain.

'Very little is known about this animal which has been recorded from about 70 places in England and Wales - it is not known from Scotland and Ireland. Of those 70 records, 22 are from Suffolk (no other county has more than 6•)' ( C r a n b r o o k , 1956). However, by the end of the 1970s the recording of this species had declined in Suffolk, and records from the 1980s are infrequent.

Present distribution and status in Suffolk Since the Suffolk Mammal Survey was launched in 1990, the Yellow-necked Mouse has been recorded f r o m 26 locations (Fig. 2). Most records have been obtained f r o m the southern half of the County, and they suggest an eastern bias. Although this no doubt reflects the distribution of recorders, rather than a reflection o f t h e species' distribution, historically the Yellow-necked Mouse has never been recorded with any frequency f r o m the northern and western parts of Suffolk. Recently Perrow et al. (1992) recorded just one specimen in their study at St. Margaret South E l m h a m in north Suffolk, from a total of 818 small mammals trapped. This individual frequented ditches with unmanaged hedgerows. There is only one record from north-west Suffolk, where one was found in a potting shed at Mildenhall ( G r a n t h a m 1958). It has never been recorded from the Santon D o w n h a m area in T h e t f o r d Forest (R. W h i t t a p e r s . comm.).

In south Suffolk it seems certain that the Yellow-necked Mouse is underrecorded, and it may well turn out to be a fairly c o m m o n species in some places. C o m p a r e d to its previous status in this part of Suffolk it is now recorded more frequently, but even here its distribution seems to be local and erratic. This is perhaps illustrated by recent work carried out by the

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Suffolk Natural History, Vol. 29 Apodemus flavicollis

Fig. 2

author in Arger Fen (TL 9335) and Spouse's Grove (TL 9336). Regulär livetrapping has been carried out in Arger Fen over a period of almost three years (1990-92) during which time many individuals of Wood Mouse and Bank Vole (Clethrionomys glareolus) have been captured, but none of the Yellow-necked Mouse. However, at the nearby Suffolk Wildlife Trust reserve, Spouse's Grove, three Yellow-necked Mice were caught, at the first attempt, in Longworth traps similarly baited as those in Arger Fen. Further trapping is required at those sites before any definite conclusions can be drawn, but it remains to be seen whether the Yellow-necked Mouse is present in Arger Fen. Clearly we need to know more about the status and distribution of the Yellow-necked Mouse in Suffolk. It is clear that they enter sheds, garages and houses, especially during the autumn, and because of this many get killed. Cats regularly catch and kill Yellow-necked Mice (Bentley, May 1992 as per C. J. Hawes, and Brightwell, March 1993 as per M. Crewe for example) and they occur as road casualties (Bentley, November 1992 as per C. J. Hawes for example, and on 12th December 1992, I killed one whilst driving at Langham, Essex).

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Whilst live-trapping is the preferred method of determining the presence of the Yellow-necked Mouse, all records, including alternative trapping methods, cat catches and road casualties, are important in building up a picture of the animal's distribution. Records of the Yellow-necked Mouse should be sent to the Suffolk Biological Records Centre. Dead specimens may also be sent there, provided they are placed in a strong plastic bag, which is then secured within strong packaging. Good specimens are alwäys required for the County mammal skin collection which is housed at the Ipswich Museum. All contributors to the Suffolk Mammal Survey will be acknowledged in ' The Mammals of Suffolk' when it is published.

Acknowledgements I thank Martin Sanford, Records Officer of the Suffolk Biological Records Centre, for producing the distribution maps and Colin Hawes for the line drawing. I also thank Peter Mudd, Warden of Spouse's Grove, and the Suffolk Wildlife Trust and Suffolk County Council for allowing me access to their reserves.

References Andrews, H. (1937). More Yellow-necked Mice. Trans. Suffolk Nat Soc 3 309. ' ' Corbet, G. & Harris, S. (1991). The Handbook of British Mammals (3rd ed.); 229-233. Oxford, Blackwells.

Cranbrook, Earl of (1952). Mammals. Trans. Suffolk Nat. Soc. 8, 4.

Cranbrook, Earl of (1956). Field Mouse Survey. Trans. Suffolk Nat Soc 9 388-9.

Cranbrook, Earl of (1968). Notes and Observations. Trans. Suffolk Nat. Soc. 14, 71.

Grantham, A. (1958).'Observations. Trans. Suffolk Nat. Soc. 10, 335.

Hancy, R. (1992). Norfolk Bird and Mammal Report 1991\ 339. Norw Norfolk and Norwich Naturalists' Society.

Hughes, F. (1986). A Provisional Atlas of the Mammals of Essex; 3 London, Passmore Edwards Museum.

Perrow, M. R., Peet, N. & Jowitt, A. (1992). The small mammals of drainage ditches- the influence of structure. Trans. Suffolk Nat Soc 28 3-9. ' ' Rackham, O. (1986). The History of the Countryside, London, Dent.

Rope, G. T. (1911). Mammals. The Victoria histories of England. Suffo Constable, Westminster.

Yalden, D. W. (1992). Changing distribution and status of small mammals in Britain. Mammal Review 22, 97-106.

J. R. Martin, 17 Moss Way, West Bergholt, Colchester, C06 3LJ

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