Distribution of Yellow-necked Mouse

DISTRIBUTION OF THE YELLOW-NECKED MOUSE Apodemus flavicollis wintoni Barrett-Hamilton in woods at Great Glemham.

The park at Gt. Glemham is some 60 odd acres in size and surrounded on all sides by woodland, mostly oak Standards and coppice, the latter mainly hazel, sycamore, ash or chestnut. On the south side of the park is a narrow belt of mixed but mainly coniferous trees. (Trap lines 3 and 4). The northern ยง of the park lies more or less on the 100 foot contour, the southern J in a Valley at about 60 feet above sea level. As is usual under such conditions in Suffolk the higher portion is typical heavy " wheat and bean land ", the lower lighter and more sandy.

Gt. Glemham House with its garden and shrubberies forms an " island " of about 7 acres more or less in the middle of the park.

A. flavicollis is found throughout the garden and shrubberies, apparently mixed with the general population of the ubiquitous A. sylvaticus in the proportion of 1:7 (Transactions S.N.S. Vol.

314

DISTRIBUTION OF THE YELLOW-NECKED MOUSE

IX pt. I p. 32). We are told that during that investigation flavicollis and sylvaticus were caught in adjoining traps and that there were no indications that flavicollis was confined to any particular area.

During the winter of 1955 /56 we made a survey of the small mammals in the woods surrounding the park using break-back traps baited with cheese. These were set in line, 10 - 20 paces apart, left in each trap line for 4 or 5 days and then moved to a fresh site. The trap lines are marked (1, 2, 3, 4, etc.) on the sketch plan and the results tabulated below.

We visited the traps daily, but had to do this as and when we could spare the time, sometimes in the morning and sometimes in the evening. Obviously, therefore, our results give no indication oie.g. the relative abundance of Clethrionomys and Apodemus : if we visited in the morning, resetting the traps, a Clethrionomys might be captured during the day when the trap would not be available for Apodemus that night, and vice-versa if we visited the traps in the evening.

Nevertheless the results do seem to indicate that A. flavicollis is found in isolated pockets amongst the general population of A. sylvaticus.

NOVEMBER 28TH.

Trap Line Trap Nights Clethrionomys A. sylvaticus A. flavicollis S. araneus S. minutus

1 24 6 2

2 32 1 4

3 24 8 4

4 32 16 5

5 32 6 3

—

—

— •

—

—

1

1

1

1

9 40 10 2

10 32 3 3

12 56

—

—

11 32 2 4 1

13 56 2 9 1 3

—

6 32 8 4 1 1

7 56 8 5 4 1

8 40 7 2 — 1

JANUARY IST.

Trap Line Trap Nights Clethrionomys A. sylvaticus A. flavicollis S. araneus S. minutus

1

2

— .

—

—

—

14 56 1 1

15 48 1 3

16 32 .—.

1

—

—

—

11 2 4 1

—

FEBRUARY IST.

Trap Line Trap Nights Clethrionomys A. sylvaticus A. flavicollis S. araneus S. minutus

3 1

—

4 —

—

1

Traps covered by snow for a fortnight.

315

DISTRIBUTION OF THE YELLOW-NECKED MOUSE MARCH 3RD.

17 18 19 20 21 Trap Line 48 48 48 48 24 Trap Nights Clethrionomys 2 1 — 2 — A. sylvaticus 1 — 3 — — A. flavicollis 1 — 1 —— S. araneus S. minutus APRIL IST.

Trap Line 22 23 24 25 26 27 28 Trap Nights 32 24 24 32 32 32 24 1 Clethrionomys 9 L 1 1 A. sylvaticus 3 2 A. flavicollis 1 S. araneus S. minutus — 1 —

—

—

—

MAY IST.

JANUARY.

30 Trap Line 32 Trap Nights Clethrionomyis 2 A. sylvaticus A. flavicollis — 9 S. araneus 1 S. minutus

Trap Line Trap Nights Clethrionomys A. sylvaticus A. flavicollis S. araneus S. minutus

31 30 —3 — 1 —1

DECEMBER.

Trap Line Trap Nights Clethrionomys A. sylvaticus A. flavicollis S. araneus S. minutus

32 36 1 1 —• 1 —•

N. CHANDLER and A. HEFFER, Gt. Glemham Natural History Club.