NEW SUFFOLK MAMMALIA
297
below Corton cliff. The former may well be as old as the Continental specimens as they are evidently derived into the Crag from an older deposit and would therefore be several millions of years old. The Corton specimen which has been referred to II. crocuta dates back about half a million years and could have been an ancestor to the Barham specimen which is probably the same species. It is hoped further remains of this rare and interesting animal will be recovered.
THE YELLOW NECKED FIELD AT STOWMARKET by W.
G.
MOUSE
THURLOW
IN an investigation carried out by H. N. Southern (of the Bureau of Animal Population, Oxford), it was found that, in one area where the choice of a river-side habitat occurred, the Yellownecked Mouse (Apodemus flavicollis zvintoni Barrett-Hamilton) was more frequently noted in the neighbourhood of the river, that flavicollis might be a water-side creature ; this, according to Lord Cranbrook, is not the case at Great Glemham. A. flavicollis was first noted at Stowmarket about 60 yards from the River Gipping, and it was decided to carry out an investigation in this locality in an attempt to determine any apparent influence the river might have upon the distribution of the Stowmarket flavicollis.
298
FIELD MOUSE AT STOWMARKET
The N.E. side of the river in the selected area is not as suitable as the S.W. side for this kind of investigation, and in the first year only one trap-line (A) was set on the N.E. bank ; no Apodemus occurred. In the second year a limited amount of trapping was done on the N.E. bank (X and Y). The area to the S.W. is low pasture, with arable land rising towards Combs Wood. Traps were set at intervals of approximately ten yards along hedgerows, in the first year mainly at right angles to the river, and in the second year roughly parallel to the river. With the exception of trap-line B, which was set under a concrete platform (an industrial relic) and trap-lines Q and S, all the traps were set for two nights in each position. They wäre baited with bread, and were camouflaged with dry grass, sticks or bricks, whichever happened to be most readily available. The traps were set as often as convenient, usually about midday, and were examined approximately 24 hours later. It is regretted that, owing to lack of time, it was not possible to record fßll details of all captures, but the intention was to retain all specimens of Apodemus with a collar or with a hind foot of 24mm. plus. The flavicollis caught in the house " Q " were incidental to the investigation. Table I gives a summary of all specimens captured, and Table II gives details of each flavicollis. It should be noted that the areas occupied by trap-lines C, D, X and Y are not grazed, thus providing good cover, and the hedge utilized for trap-lines C and D was, at the time of the investigation, sheltered by derelict buildings. Owing to the small number of specimens of Apodemus caught away from the river, the results obtained are inconclusive ; it is probable that the nature of the habitat in the immediate vicinity of trap-lines C and D is more conducive to the occurrence of small mammals in general. It is evident that more trapping will need to be done away from the river, preferably using a discriminating bait, so as to prevent traps being sprung by voles and shrews. (It is assumed that many of the large proportion of sprung but vacant traps were released by shrews, these mammals being sufficiently small to evade capture.) I would like to acknowledge the encouragement given by Lord Cranbrook in this investigation, and the practical assistance given by Member A. D. Rowe and Mr. K. I. Last.
299
FIELD MOUSE AT STOWMARKET TABLE
I.
Trap-Hedge/ line Ditch A
—
B
—
C
D E F G
H
J
K L M N
O P
Q R S T U V
w
H.D. H.D. H.D. H.D. H. H. H.D. D. H.D. H.D. H.D. H.D. H.D. —
D. D. H.D. H.D. H.D. H.D.
X
—
Y
—
Date
Trapnights
11, 1 2 / 3 / 5 7 5 13 157 28/2, 4 / 3 / 5 7 13, 1 4 / 3 / 5 7 18, 1 9 / 3 / 5 7 25, 2 6 / 3 / 5 7 22, 2 3 / 3 / 5 7 20, 2 1 / 3 / 5 7 27, 2 8 / 3 / 5 7 18, 1 9 / 3 / 5 7 20, 2 1 / 3 / 5 7 25, 2 6 / 3 / 5 7 27, 2 8 / 3 / 5 7 29/3, 1/4/57 2, 3 / 4 / 5 7 14, 1 5 / 1 0 / 5 7 4, 5 / 3 / 5 8 6/3/58 10, 1 1 / 3 / 5 8 12, 1 3 / 3 / 5 8 17, 1 8 / 3 / 5 8 19, 2 0 / 3 / 5 8 24, 2 5 / 3 / 5 8 26, 2 7 / 3 / 5 8
11 6 12 10 10 12 12 12 12 8 8 12 12 24 24 ? 12 6 12 12 12 12 12 12
TOTALS
TABLE
„ | £-5 2
—
1 —
— —
1
| S
| | b "
| | S-5
|.g S&
2
—
—
—
1 3
—
2 1 3 1 2 1 2 2 1 3
—
—
—
—
—
—
—
—
—
2
— —
—
—
—
1
— —
—
2
5
1
—
2 3
—
—
3
—
Date 4/3/57 13/3 /57 14/3/57 14/10/57 14/10/57 14/10/57 15/10/57 15/10/57
—
—
—
—
—
—
—
—
—
—
1 1
— — —
1
— —
—
—
—
—
5 —
—
1 2
—
— —
—
8
—
—
—
1
—
—
—
1
—
—
—
—
1
—
—
—
—
—
—
2
—
1
1
1 1 15
—
—
—
—
28
—
1 —
1
11
flavicollis
Sex M F F F M M M M
1 2 —
II.
DETAILS OF Apodemus
Trapline 1 C 2 D 3 D 4 Q 5 Q 6 Q 7 Q 8 Q
Kg
Head and body Tail (mms.' nms.) 94 115 99 97 84 94 80 94 94 100 93 91 88 100 94 96
Distance Hind from foot Weight river (mms.) (gms.) (yards) p 29.4 61 22 30.1 109 23 23.1 79 23 23.65 c.180 24 29.0 c.180 24 21.3 c.180 23 23.0 c.180 23 23.0 c.180
— —
8