Cl °LTJRr BROOM
SHREWS
as
TREE SEED EATERS
in the
DOUGLAS FIR REGION
By
FEB 21 19
DR. RUDOLPH KANGUR
MTE 0j
OREGON STATE BOARD OF FORESTRY
George Spaur, State Forester
Dick Berry, Research Director
Salem, Oregon
v
'e4,ea4d Itate 72a, /7
SHREWS
as
TREE SEED EATERS
in the
DOUGLAS FIR REGION
By
DR. RUDOLPH KANGUR
OREGON STATE BOARD OF FORESTRY
George Spaur, State Forester
Dick Berry, Research Director
Salem, Oregon
DECEMBER 1954
This study made possible by funds derived through
the Oregon Forest Research and Experimental Tax Act
of 1947 and the Oregon Revised Statutes, Chapter 321.
TABLE OF CONTENTS
Page
FOREWORD
ABSTRACT
------ ------------------------------------ ---------------- ----------------------------------- --------
1
2
----------------------------------------------------------------------------------
INTRODUCTION
3
-
PURPOSE OF STUDY ---
REVIEW OF LITERATURE
4
4
-------------
EXPERIMENTAL PROCEDURES ----------------------------------------------------------------------General ----------------------------------------------------------------------------------------------------------
Location and Description of Study Areas
Cage Tests -
Trapping Checks
Acceptance Spots
----------- .--------------------------- -----------
-------------------------------------------------- ------------------------------------------------------------------------------------------------------------------------------------- ---------------------- -------------------------------------- -----------
RESULTS ---------------------------------------------------------------------------------------------------Cage Tests ---- --------
---------- ------------------------------------------
---------------------------- ------ -----
Rockaway (Table 1) .---------- -- ---------------------------------------------------Camp Rogers (Table 2) -----------------------------------------------------------------------------Trapping Checks (Table 3) ----------------------------------------------------------------------Acceptance Spot Results
.........----------- -------------- --------------------------------------------------
Rockaway-Screened Douglas Fir (Table 4) --------- ------------------- ...-.----- ..-Camp Rogers-Screened Douglas Fir (Table 5) ------------------- -------- --------Rockaway-Unscreened Douglas Fir (Table 6) ------------------------------------
Camp Rogers-Unscreened Douglas Fir (Table 7) ..............................
Rockaway-Unscreened Spruce (Table 8)
--------------------------------------------
Percent Seed Taken on Screened Spots (Figure 1) ------------------------------
Percent Seed Taken on Unscreened Spots (Figure 2) ..........................
CONCLUSIONS
BIBLIOGRAPHY
-------
------------------_--------------------------------------------
-------------
22
23
FOREWORD
Dr. Rudolph Kangur, author of this report and staff member
of the research section of the Oregon State Board of Forestry, has
quite a varied and interesting background. Dr. Kangur was born
in Estonia in 1905; was educated there and received his professional
degrees at the University of Tartu (Estonia). His early years as
a forester were spent there as a manager of public forests. Later
he worked as an assistant on the staff of the University of Tartu.
His speciality is in the field of selective management. With the
advance of the Russians into Estonia in September, 1944, during
World War II, Dr. Kangur and his family attempted an escape to
Sweden across the open sea in a rowboat only to be picked up by
the crew of a German submarine. His political views not being in
accord with those in vogue in Germany at the time, he ended up in
the Dachau concentration camp. He was separated from his family
whom he did not hear from again until after his liberation by the
Americans. After the end of the war he worked for several years
as a forester for the West German Government and finally, in 1949,
was able to come to the United States.
He immediately applied for citizenship papers and shortly thereafter was employed by the Oregon State Board of Forestry. Dr.
Kangur expects his final citizenship papers sometime in 1955.
Dr. Kangur speaks conversational English quite well but he felt
his progress as yet not quite up to the written report. It is for
this reason that I have quite freely edited the original manuscript.
DALE N. BEVER
Research Forester
[11
ABSTRACT
This study was undertaken to provide more information concerning the food habits of shrews. Quantity consumption of tree
seeds and the seasonal fluctuations in acceptance of tree seeds
were the main objectives considered.
Experimental procedures were limited to cage tests and field
acceptance tests. The tree seeds tested were Douglas fir and Sitka
spruce. There were two main study areas. One study area was
at Rockaway, in the coast Sitka spruce-west coast hemlock type,
and the other was near Camp Rogers in the Tillamook Burn, in
the Douglas fir type.
The results of the study showed that shrews, although classed
as insectivores, were eating a great amount of tree seed. In captivity
they ate from 185 to 250 Douglas fir seeds in a 24 hour period
(this much seed is equivalent to one-half their body weight). In
the field they took from 50 to 100 per cent of all Douglas fir seed
placed in acceptance spots in each three-day test period. Sitka
spruce, usually considered to be safe from seed eating mammals,
was taken from 15 to 55 per cent. The amount of "take" varied
with the season of the year. More tree seeds were eaten in the
winter and early spring when natural foods were scarce. Less
were eaten in the late summer and fall when natural foods were
more abundant.
The general conclusion reached was that positive control measures
for shrews, as well as for deer mice (Peromyscus), is a must for
any direct seeding project, or for any program of baiting mammals
to protect natural seed fall.
C2]
INTRODUCTION
The search for better control of small seed eating mammals is
receiving more and more attention. The protection of high priced
tree seed on artificially seeded areas and the protection of natural
seedfall are both of great concern to forest managers.
In the Pacific Northwest the emphasis has been on the control
of the white-footed mouse (Peromyscus maniculatus rubidus), as
this is undoubtedly the most destructive of the seed eaters in the
Douglas fir region. In all experimental and project seedings snap
traps, live traps or acceptance spots have been used to determine
the effectiveness of control measures. In all of these checks shrews
have been caught or there has been evidence of shrews taking tree
seed. Ordinarily this has not caused too much concern as the
shrews, classed as insectivores, were not usually caught in any
great numbers; and, even where they appeared in heavier populations, it was generally assumed that tree seeds were a minor part
of their normal diet.
Articles by A. W. Moore (4) and (5) and observations made
by field workers currently studying the small mammal seed eaters
have recently reopened the question of the importance of shrews
as tree seed eaters.
131
PURPOSE OF STUDY
The Oregon State Board of Forestry initiated this study to learn
more about shrews and their role as tree seed eaters. The study
was designed to answer the following questions:
1. Will shrews eat Douglas fir or Sitka spruce seed in quantities sufficient to be detrimental to seeding?
2. What is the relative acceptance of tree seed by shrews
during different seasons of the year?
REVIEW OF LITERATURE
Physical Description
The shrew is one of the insectivores. This family, near the
bottom of the mamal family tree, is known as the Soricidae, from
the Roman name Sorex for the shrew. They are exceedingly delicate
little creatures, the smallest of mammals. So far as is known,
Palmer's shrews (Sorex bendirii palmer) are largest (total length
adult male is 165 mm; tail 73 mm), and Vagrant shrews (Sorex
vagrans vagrans) are smallest (average adults 104 mm; tail 42 mm;
wt. 7 gms.) of Oregon shrews. Average weight of all species of
shrews is approximately 12 gr. (1)
The fur of shrews is very fine and the colors vary from dusky
grey to blackish brown; their form is mouse-like in appearance.
The skulls are long and narrow with long tapering snouts, which
are so well supplied with delicate bristles that it seems probable
that the senses of smell and touch take the place of sight to some
extent. The eyes are very small. They have complexly infolded
ears that are often almost buried in the fur, and numerous small,
sharply-pointed, orange colored teeth.
Habitat
Shrews are widely distributed and are quite abundant in Douglas
fir and Sitka spruce areas in northwest Oregon, principally on the
coast in the fog-belt area and in the coast range. There are nine
subspecies of shrews in the Douglas fir region. Some are more
abundant than others.
They live in close association with mice and use burrows made
by mice under the logs, rocks, leaves and grass. They are seldom
seen and are very fast moving. They seem to glide along rather
than run. They are nocturnal, not active during the daytime
except during cloudy weather or under the snow in winter. They
do not hibernate in winter.
Breeding Habits
Very little is known in regard to the nest and home life. The
nests are made of grass and leaves under logs and rocks, in stumps
14]
and in similar situations. Each year, between early spring and
late summer, they bear from one to four litters of up to nine young
per litter. Some biologists think that they do not breed in their
first year and die at the end of their second breeding season. Because large numbers are found dead in the fall, other biologists
believe that they may be annuals; only the young ones of the year
living through the winter to the next year.
Feeding Habits
It has been so difficult to keep shrews in captivity that most
studies of the feeding habits of shrews are based mainly on stomach
examinations. The following have been found among stomach contents: Hymenoptera, C o l e o p t e r a, Diptera, caterpillars, crickets,
spiders, hair and flesh of shrews and mice; moss, seeds and a variety
of other vegetable material.
Studying the feeding habits of shrews living in northwest Ore-
gon, Moore (4) stated that plant materials comprised 61.25 per
cent of the total stomach contents of 17 shrews. Douglas fir seed
fragments made up 24.40 per cent of all the food content.
The voracious appetites of shrews seem to goad them into
incessant activity. Their digestion is rapid and the amount of
food eaten in 24 hours is equal to their own weight. Their lives
appear to be little more than a continual quest for food.
EXPERIMENTAL PROCEDURES
General
The answers to the questions were sought in the field by the use
of two separate techniques, as follows:
1. See consumption by caged shrews.
2. Seed consumption on acceptance spots. The acceptance
spots were divided into those which were screened to
exclude mice and those which were not screened and so
were available to both shrews and mice.
The study was conducted simultaneously in both the Douglas fir
type and the fog-belt (Sitka spruce-west coast hemlock) type.
Location and Description of Study Areas
The study areas were selected in the spring of 1952.
Rockaway, the first selection, is along the Oregon coast in the
fog-belt type. The original stand of west coast hemlock and Sitka
spruce was logged in 1949 and 1950. The heavy slash on the cutover
had not been burned. The area was bordered from the southwest,
to the northwest by standing timber. Green ground cover varied
[51
from light to medium and consisted of mosses, oxalis, miners lettuce,
salmonberry, sword fern and salal. (See Plate 1)
Camp Rogers, the second selection, is in the Tillamook Burn.
The area had been burned three times since 1933, the last in 1945.
Heavy green ground cover consisted of willows, vine maple, bracken
fern, blackberry, salal, Oregon grape, and many varieties of annuals
such as birds-foot trefoil, many-leaved pea, wild bleeding heart and
grasses. (See Plate 2)
Cage Tests
Inasmuch as shrews are quite difficult to keep in captivity, the
cage tests were conducted in the study areas. The cages were
placed in natural surroundings and were not moved from the time
the shrew was caught until its death. Even with this precaution
the longest these small insectivores remained alive was three to
four days.
The cages were constructed of 1/4 inch mesh galvanized hardware cloth with a 1/4 inch plywood bottom. They were connected
with a Sherman-type live trap. The trap entrance was covered
with 1/2 inch mesh hardware cloth to prevent entry of the larger
mammals. The rear end of the live trap opened into the larger cage.
An ample supply of materials from the local vegetative ground
cover were placed in the cage to simulate natural nesting conditions.
(See Plate 3)
Douglas fir seeds were counted and placed in the cage for food
and in the trap for bait. In some of the cages there were also placed
worms, ground beetles, meat, etc., to give the shrews a choice of
food.
Once a shrew was caught in a cage it was given water and a
known number of Douglas fir seeds daily.
Upon the death of the shrew the contents of the cage were removed to a cloth where the remaining uneaten seeds were carefully
counted. In this manner the total seed consumption of the shrew
was determined for the period of captivity.
Trapping Checks
In order to keep a continual check on whether mice were entering screened spots the study areas were trapped at least every other
month. All trapping was done at sufficient distances from the
acceptance spots so as not to disturb populations in the immediate
vicinity. Forty snap-type mouse traps, baited with peanut butter
and Douglas fir seed, were placed in a rectangular area of .44 acres.
Traps were placed at intervals of 22 feet in five rows of eight traps
to a row. Each trap was covered with a cylinder of 1/z inch mesh
hardware cloth.
[s]
-Photograph by W. H. Engstrom
Plate I.
Rockaway Area Near the Oregon Beach
-Photograph by W. H. Engstrom
Plate 2.
Camp Rogers Area
171
a
31
15
I
t
1.
r
IL
-Photograph by W. H. Engstrom
Plate 3. Field-Cage and Trap
Acceptance Spots
Checks on seed consumption by use of acceptance spots were
carried on in both study, areas from March, 1952 to February, 1953.
Three permanent plots within the Rockaway area were chosen and
two permanent plots were chosen within the Camp Rogers study area.
The plots at Rockaway were for screened Douglas fir, unscreened
Douglas fir, and unscreened Sitka spruce. The plots at Camp Rogers
were for screened Douglas fir and unscreened Douglas fir. Each
plot consisted of forty spots with the spots arranged in an identical
pattern to the trap plots (five rows of eight spots each with 22
feet between spots and rows).
Screened spots were covered with the same type of hardware
cloth cylinder and was used to cover the snap traps. These cylinders
were made of 1/z inch mesh, six inches in diameter, eight inches
long, and were closed at the top with a circle of the same material.
(See Plate 4)
All spots were prepared by clearing to mineral soil an area ten
inches in diameter. Each spot received ten seeds each month.
These seeds were covered with bark to prevent washing away,
blowing away, or molesting by birds.
[sl
$
_.
.mar.
!....T` A j`.- ",. y ,'
;V AD
-owl
3k riwS-
r
x, S'
V
Al,
4911', W
-Photograph by W. H. Engstrom
Plate 4.
Screen Used to Exclude Rodents from Acceptance Spots
Spots were checked for two days after seeds were placed. Hulls
were examined carefully to determine whether the seed had been
eaten by mice or shrews on the unscreened spots. (See Plates 5
and 6)
RESULTS
The results are presented in the following pages, mostly in the
form of tables and graphs.
Cage Tests (See Tables I and 2)
During the entire period of the study only thirty shrews were
caught in the cages. Of these only seventeen lived in the cages for
two or more days. The over-all average Douglas fir seed consumption for all thirty caged shrews in a 24 hour period was 180 seeds.
This figure could be quite misleading due to the fact that the exact
time of death of most of the shrews was not known (it was only
possible to place the time in a 24 hour period). It is for this reason
that the average seed consumption of the two Trowbridge shrews
for which the exact time of death is known is particularly interesting. One of these shrews lived four days and ate an average of
242 seeds per day. and the other lived three days and ate
average of 248 seeds per day.
an
Both died during checking operations.
The availability of a wide variety of foods in some of the cages
did not appreciably reduce the average amount of Douglas fir
seed taken.
Keeping shrews in captivity appeared to be more successful in
the fall and winter than in the spring and summer.
191
I
i
F
Ip
rA
lsti:
-Photograph by W. H. Engstrom
Plate S.
Hulls of Douglas fir seeds left by mice. Note typical "Kyak" shape
and clean-cut edges.
K
J T.
0
L=j
6
-Photograph by W. H. Engstrom
Plate 6.
Hulls of Douglas fir seeds left by shrews: Note shredded appearance
and typical serrated edges.
Table
I
CAGE TESTS-ROCKAWAY AREA
FOOD SUPPLY
CATCH
m
Fed in Captivity
a
Is
a
1st Day
NN
Oy
WH
P] U
0
3rd Day
2nd Day
w
VI
F
A
3-24
4-22
4-22
5-12
6-3
6-3
7-14
9-8
9-8
10-14
10-14
11-18
12-18
1-12
1-12
2-9
2-9
3-25
4-23
4-25
5-13
6-4
6-5
7-15
9-9
9-10
10-15
10-16
11-19
12-19
1-13
1-13
2-10
2-11
]
A
T
i
En
50
300
V
50
300
T
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
T
T
B
B
T
B
T
T
V
T
T
B
T
T
ul
0
1
0)
aM
6
0
300
300
Ib
v
cSv,
0
300
350
350
650
650
350
350
950
650
950
350
300
300
300
300
300
300
X
300
X
300
300
X
300
X
1,250
300
X
1,250
350
300
300
X
300
300
300
X
X-Denotes the availability of additional food such as worms, beetles, meat, etc.
T-Trowbridge shrew--Sorex trowbridgii trowbridgii.
B-Baird shrew-Sorex bairdii.
X
350
1,250
950
Average
V-Vagrant shrew-Sorex vagrans vagrans.
Ha
1,250
300
300
UI
1
a
W 0
Q W
I
CC
Fi
a
3-28
4-23
4-25
5-14
6-5
6-5
7-15
9-11
9-11
10-17
10-16
11-22
12-19
1-16
1-13
2-13
2-13
z
E rig
969
210
242
210
1
127
127
2
237
361
234
118
180
4
1
2
1
1
3
2
3
1
4
1
4
1
4
3
111
749
451
576
219
737
206
562
133
828
486
----------------------------------------------------------------
234
111
248
225
192
219
184
206
140
133
207
162
185
Table 2
CAGE TESTS-CAMP ROGERS AREA
CATCH
FOOD SUPPLY
y
U
06
N
v
W
y
qF
Y
F
]
Fed in Captivity
3rd Day
1st Day
A
Om
Dm
qii
N
a
y
a
0
Dm
0
Dm
O
6-18
T
50
300
7-7
7-8
V
50
300
8-4
8--5
50
300
9-2
9-4
50
300
9-2
9-4
50
300
10-20
10-21
50
300
11-24
11-25
T
50
300
300
12-22
12-23
V
50
300
300
1-19
1-20
T
50
300
300
2-17
2-19
50
300
2-24
2-25
T
50
300
300
300
2-24
2-26
V
50
300
300
300
T
B
B
V
300
FA
300
a
z
w0
y
QW
N
N fJ
Ci
Hm
W
6-18
1
145
145
7-8
1
118
118
8-6
2
409
205
9-4
1
212
212
9-6
2
183
91
10-21
1
159
159
950
11-27
3
575
171
650
11-24
2
361
180
650
1-21
2
452
226
2-19
1
185
185
1,250
2-28
4
843
210
950
2-27
3
617
205
650
300
j',
RN
650
300
m
o
a
6-16
T
A
2nd Day
a
.
Y
P
j
Snap Trapping (See Table 3)
The check trapping with screened snap traps was quite con-
clusive. Thirty-one shrews were trapped in a twelve month period
in traps protected by screen cylinders of 1/2 inch mesh hardware
cloth. In all this time not one mouse was caught. From this it
can be fairly well assumed that the screens were effective in
keeping the mice out of the acceptance spots which were protected
with the same type of screen cylinders. As further evidence of
this it should be noted that in all this time no mice were caught
in the cages in which the entrances to the Sherman live traps were
covered with the 1/2 inch mesh hardware cloth.
Table 3
TRAPPING SUMMARY-1952-1953
TRAPS SCREENED WITH ONE-HALF INCH MESH CYLINDERS
CATCH
a
First Night
Rockaway Area
Second Night
Camp Rogers Area
Total
First Night Second Night
Total
o
a
v
a
a
v
a
v
ai
5
m
u
m
1.
1
2
0
a
ai
Am
4 E.
U.,
3-26
40
2
2
4-3
40
5-14
40
2
2
6-3
40
7-3
40
8-6
40
8-13
40
2
9-11
40
3
10-22
40
11-20
40
12-22
40
1-14
40
2-16
40
2-11
40
3
a
a
a
V1
2
a
N
a
v
2
3
1
3
1
2
3
5
1
1
a
2
3
2
1
2
2
1
1
3
1
1
1
L
1.3
1
Acceptance Spot Results (See Tables 4, 5, 6, 7, 8; Figures I and 2)
The results, in terms of percentage of seeds taken, of the data
in Tables 4 and 5, are presented in graphical form in Figure 1.
Figure 2 gives the same graphical representation of the data pre-
sented in Tables 6, 7 and 8. In general terms, the acceptance spots
showed that, when mice were excluded, the shrews, within two days,
consumed an average of 70 per cent of all seeds placed in .the field.
The shrews showed a quick reaction to the seed as evidenced by
the fact that 60 per cent were taken the first night.
On unscreened Douglas fir spots, where mice were not excluded,
the take was very high in all cases (96 per cent at Rockaway and
89 per cent at Camp Rogers). On the Rockaway plot, where such
records were kept, the shrews were taking 67 per cent of the seed
eaten even though the seed was equally available to both shrews
and mice.
On the unscreened spruce plot the number of plots visited on
the first night, the number of seeds taken the first night, and the
total number taken for both nights were low in comparison to the
Douglas fir take. Even here, however, the shrews and mice in
two nights were taking an average of slightly better than one-third
of the seed of a species usually considered safe from the seed eaters.
The seasonal fluctuations in seed consumption for all seed tested
in both areas and under all test conditions was about as expectedthe amount of seed eaten was greatest in the winter when less other
food was available and least in the fall when the maximum of other
food was available. This held true whether for shrews alone or
for both shrews and mice.
[14]
Table 4
ROCKAWAY-SCREENED DOUGLAS FIR
Seeds
Seeds
Seeds
Spots
TOTAL
SECOND NIGHT
FIRST NIGHT
8
0
w
'0
NW
yY
h
'
O NY
Id
cu
10
z
R N
U N
95.55
228
63
27.63
65
63
96.92
235
58.75
v
V
N
zw
wID
a"$
zv
45.00
43.00
19
47.50
45.25
190
181
95.26
219
113
51.59
113
113
100.00
294
73.50
33
82.50
82.50
330
330
100.00
70
50
71.43
50
50
100.00
380
95.00
333
97.94
67
41
61.19
41
41
100.00
374
93.50
60.00
3-24
18
4-22
5-1.2
6-3
172
Q nj
r"
c,
a
180
O
34
85.00
83.25
340
7-1
15
37.50
37.50
150
150
100.00
250
90
36.00
90
90
100.00
240
7-14
26
65.00
63.50
260
254
97.69
146
86
58.90
86
86
100.00
340
85.00
8-11
31
77.50
69.75
310
279
90.00
121
78
64.46
79
78
98.73
357
89.25
92
51.10
92
92
100.00
311
77.75
9-9
24
60.00
54.50
240
218
90.83
182
9-30
30
75.00
66.25
300
265
88.33
135
33
24.44
45
33
73.33
298
74.50
10-14
31
77.50
61.00
310
244
78.70
156
56
35.90
68
56
82.35
300
75.00
71.75
300
287
95.67
113
43
38.05
43
43
100.00
330
82.50
100.00
400
100.00
11-18
30
75.00
38
95.00
95.00
380
380
100.00
20
20
100.00
20
20
1-12
35
87.50
84.00
350
336
96.00
64
40
62.50
42
40
95.24
376
94.00
2-9
33
82.50
81.25
330
325
98.48
75
62
82.67
64
62
96.87
387
96.75
12-8
Table 5
CAMP ROGERS-SCREENED DOUGLAS FIR
FIRST NIGHT
Spots
ro
°~
21,
>
SECOND NIGHT
TOTAL
Seeds
Seeds
Seeds
ro
o
x°
Y
w
v
N-
a°
v
zo
oaro
.
ro
vs
O
S' 7
O 0
N
NY
v
Y
N
y
R °
o
0ro
aw w
a1
zo
113
44.49
129
113
87.60
259
64.75
248
93
37.50
116
93
80.17
.245
61.25
66.67
260
134
51.54
142
134
94.37
274
68.50
367
99.19
33
13
39.39
13
13
100.00
380
95.00
320
206
64.37
194
68
35.05
68
68
100.00
274
68.50
220
181
82.27
219
109
49.77
109
109
100.00
290
72.50
45.25
200
181
90.50
219
89
40.64
97
89
91.75
270
67.50
55.00
23.00
220
92
41.82
308
70
22.73
120
70
58.33
162
40.50
35
87.50
80.00
350
320
91.43
80
51
63.75
56
51
91.07
371
92.75
33
82.50
76.75
330
307
93.03
93
48
51.61
49
48
97.96
355
88.75
12-22
38
95.00
92.00
380
368
96.84
32
28
87.50
28
28
100.00
396
99.00
1-19
31
77.50
60.50
310
242
78.06
158
67
43.40
79
67
84.81
309
77.25
2-17
24
60.00
34.50
240
138
57.50
262
101
38.55
121
101
83.47
239
59.75
°
°
aroi
yaroi
m
zQ
as
4-1
15
37.50
36.50
150
146
97.33
254
4-15
18
45.00
38.00
180
152
84.44
5-1.9
21
52.50
35.00
210
140
6-1
37
92.50
91.75
370
6-16
32
30.00
51.50
7-7
22
55.00
45.25
8-4
20
50.00
9-2
22
10-20
11-24
Table 6
ROCKAWAY-UNSCREENED DOUGLAS FIR
Spots
oN
so.o
v
ro
0
v
'av z4y
P,z0
o
NN
x
m
ro
pxy
°x
.' O
u'O
o
a
I
3-24
40
100.00
100.00
400
Seeds
Seeds
Seeds
ro
TOTAL
SECOND NIGHT
FIRST NIGHT
400
100.00
0
ro
w
e>
E'd
zo
z.
x
v
C v
.14
oyw
u.
aw
a
10
10
100.00
10
10
100.00
.0
v
'co
o
z
7v
v00
S
o
um
v$
I
w
o
uh
v
aO
400
100.00
77.5
400
100.00
82.5
4-22
39
97.50
97.50
390
390
100.00
5-12
40
100.00
100.00
400
400
100.00
400
100.00
70.0
6-3
40
100.00
98.75
400
395
98.75
5
5
100.00
5
5
100.00
400
100.00
70.0
390
100.00
10
10
100.00
10
10
100.00
400
100.00
67.5
70.0
7-1
39
97.50
97.50
390
7-14
39
97.50
97.25
390
389
99.74
11
11
100.00
11
11
100.00
400
100.00
8-11
40
100.00
99.50
400
398
99.50
2
2
100.00
2
2
100.00
400
100.00
55.0
9-9
9-30
19
47.50
44.50
190
178
93.68
222
23
10.36
23
23
100.00
201
50.25
30.2
40
100.00
100.00
400
400
100.00
400
100.00
60.0
10-14
40
100.00
100.00
400
400
100.00
400
100.00
65.0
11-18
39
97.50
97.50
390
390
100.00
400
100.00
57.5
400
400
100.00
400
100.00
62.5
68.0
65.0
12-8
40
100.00
100.00
10
10
100.00
10
10
100.00
1-12
40
100.00
95.50
400
382
95.50
18
11
61.11
12
11
91.67
393
98.25
2-9
15
37.50
37.50
150
150
100.00
250
210
84.00
210
210
100.00
370
92.50
Table 7
CAMP ROGERS-UNSCREENED DOUGLAS FIR
FIRST NIGHT
Spots
I
C)
OE
aCi
a;
o.
5
0
Sy
dN
TOTAL
Seeds
Seeds
o
LA
v
yA
#
0
8u
o v
uv
R
J w
z
z8
ay
QI V
4-1
18
45.00
43.00
180
172
95.55
228
108
47.37
4-15
15
37.50
37.50
150
150
100.00
250
60
5-19
30
75.00
74.25
300
297
99.00
103
6-1
39
97.50
97.50
390
390
100.00
6-16
40
100.00
96.50
400
386
7-7
39
97.50
94.75
390
8-4
9-2
38
95.00
95.00
23
51.50
10-20
40
11-24
a
zo
v
CC
y
W 0 0.
w
-9 co
vy%
LL
y o
v
v
w
m
Rw
z
C
)
0
'0
v1°
0
av
UN
yo
r
ao
SECOND NIGHT
Seeds
3N
y 0 0
C
m
0
Rw
00
7i rrt
a ma
zv
108
108
100.00
280
70.00
24.00
60
60
100.00
210
52.50
22
21.36
22
22
100.00
319
79.75
10
10
100.00
10
10
100.00
400
100.00
96.50
14
14
100.00
14
14
100.00
400
100.00
379
97.18
21
9
42.86
9
9
90.00
388
97.00
380
380
100.00
20
16
80.00
16
16
80.00
396
99.00
48.75
230
195
87.78
205
178
86.83
178
178
96.22
373
93.25
100.00
100.00
400
400
100.00
400
100.00
39
97.50
97.50
390
390
100.00
10
8
80.00
10
8
80.00
398
99.50
12-22
37
92.50
91.00
370
364
98.38
36
26
72.22
26
26
72.22
390
1-19
97.50
35
87.50
84.50
350
338
96.57
36
18
29.03
18
18
90.00
2-17
356
89.00
32
80.00
75.50
320
302
94.38
98
19
19.39
19
19
79.17
321
80.25
0
ag
Table 8
ROCKAWAY-UNSCREENED SPRUCE
FIRST NIGHT
Spots
SECOND NIGHT
Seeds
TOTAL
Seeds
Seeds
2J
wy
a
u«".
zQ
x
d
P
v.
vi
w
b
ox is
o°
1°
4+d
aw
A
a
aR
a
zo
zv
a
zro
a«
A
G
v
uo
aY
vm
P
P°
£a
zo
z w«a
N
Ay
80
a
o
O
Ro
z
Ezs
F
v
t6 ...
A+'N
0
v C)
u
N
a4
4-23
11
27.50
16.50
110
66
66.00
334
83
24.85
130
83
63.85
149
37.25
5-13
15
37.50
24.75
150
99
66.00
301
74
24.58
120
74
61.67
173
43.25
6-4
12
30.00
19.75
120
79
65.83
321
71
22.12
89
71
79.77
150
37.50
7-15
9
22.50
16.50
90
66
73.33
334
62
18.56
79
62
78.48
128
32.00
8-12
15
37.50
30.25
150
121
80.67
279
83
29.75
100
83
83.00
204
51.00
9-10
5
12.50
8.00
50
32
64.00
368
20
5.16
50
20
40.00
52
13.00
10-1
10
25.00
16.75
100
67
67.00
333
41
12.31
55
41
74.55
108
27.00
10-15
11
27.50
18.50
110
74
67.27
326
29
8.90
62
29
46.77
103
25.75
11-19
8
20.00
17.00
80
68
85.00
332
54
16.27
78
54
69.23
122
30.50
17
42.50
32.00
170
128
75.29
272
97
35.66
145
97
66.91
225
56.25
1-13
9
22.50
18.50
90
74
82.22
326
25
7.67
53
25
47.17
99
24.75
2-10
8
20.00
15.25
80
61
76.25
339
38
11.21
78
38
48.72
99
24.75
12-8
ACCEPTANCE SPOTS
PERCENT SEED TAKEN ON SCREENED
90
80
70
%
/
30
0
K
V
Z
Q
ROCKAWAY AREA - D.F.SPOTS SCREENED TO EXCLUDE MICE.
--_-..--...BOWL AREA- OF. SPOTS SCREENED TO EXCLUDE MICE:
(CAMP ROGERS)
FIGURE
L20]
I
PERCENT SEED TAKEN ON UNSCREENED ACCEPTANCE SPOTS
100
90
It
I
80
20
10
ROCKAWAY AREA - UNSCREENED D. F. SPOTS
ROCKAWAY AREA - UNSCREENED SPRUCE
ROCKAWAY AREA- UNSCREENED OF. SPOTS
PERCENT TAKEN BY SHREWS ONLY)
OWL AREA -UNSCREENED OF. SPOTS
(CAMP ROGERS)
F
I
GURE
[211
2
CONCLUSIONS
The answer to the question, "Will shrews eat Douglas fir or
Sitka spruce seed in quantities sufficient to be detrimental to the
species regeneration?", is yes. The speed of reaction of shrews to
seed placed in the field, coupled with their voracious appetites,
makes them a real factor to be considered when contemplating
direct seeding. Where limited amounts of seed were available the
shrews were finding and eating more of the seed than the mice.
In captivity the small insectivores were consuming approximately
one-half their own body weight in tree seed each day.
The answer to the question "What is the relative acceptance of
tree seed by shrews during the different seasons of the year?",
can be given in general terms only. These tests showed that seasonal fluctuations in seed acceptance in general were the same as
for mice, i.e., high during the winter months when other food supplies were scarce and lowest in the early fall when natural food
supplies were at their maximum. (See Figure 1).
Little is yet known about the evaluation of shrew populations.
It is also not known whether present baiting practices considered
adequate for control of mice is equally effective for control of
shrews. These studies should be continued and possibly intensified,
especially in the coastal fog belt where it appears that shrews in
many places may outnumber mice.
The results of this study would indicate that, on areas where
resident populations of shrews exist, it would be unwise to attempt
reforestation by direct seeding without adequate control measures.
[22]
BIBLIOGRAPHY
1.
Bailey, V.
1936
The mammals and life zones of Oregon. North Amer.
Fauna 55, 416 pp., illus.
2.
Hamiltin, W. J., Jr.
1930
The Food of the Soricidae. Jour. Mamm., 11(1) :26-30.
3. Jackson, Hartley H. T.
1928
A taxonomic review of the American long-tailed shrews.
(Genera Sorex and Microsorex) North Amer. Fauna 51,
238 pp.
4. Moore, A. W.
1940
Wild animal damage to seed and seedlings on cut-over
Douglas-fir lands of Oregon and Washington. Technical
Bulletin No. 706. U. S. Dept. of Agriculture, 28 pp.
5. Moore, A. W.
1942
Shrews as a check on Douglas-fir regeneration. Jour.
Mamm., 23(1):37-41.
[231