Greenland Barnacle Geese in the British Isles
M . A . O G I L V I E AND H . B O Y D
Introduction
T here are tw o populations o f B arnacle Geese
B ranta leucopsis wintering in the British
Isles. The sm aller one, breeding in Svalbard
(Spitsbergen) and wintering exclusively in the
Solway Firth, has been m onitored closely for
m any years (R oberts, 1966; Ogilvie, 1970;
Owen & C am pbell, 1974). T his paper con­
cerns itself with the other, larger population,
which breeds in E ast G reenland and in winter
is found alm ost exclusively on islands off
the w est and no rth coasts o f Ireland and
Scotland. The virtually com plete separation
o f the tw o populations from each other and
from a third which breeds in arctic U SSR and
w inters in the N etherlands has been show n by
extensive ringing (Boyd, 1964; L arsen &
N orderhaug, 1964; Salom onsen, 1967).
The Wildfowl T ru st has been m onitoring
the G reenland B arnacle G eese in w inter since
1957, by m eans o f occasional aerial surveys,
the m ajority over the whole range, and by
regular counts on the island o f Islay in the
In n e r H e b rid e s th a t have also in clu d ed
assessm ents o f annual breeding success. Islay
holds a considerable m ajority o f the total pop­
ulation. Virtually the only other w ork on the
p o p u latio n h as been by C a b o t on th e
Inishkeas, the m ost im portant Irish haunts,
which he has visited alm ost annually since
1960 (C abot & W est, 1973). H e has been
concerned with the population dynam ics o f
the 2 ,0 0 0 -2 ,5 0 0 b ird s w in terin g on th e
islands and with looking for factors which
m ay affect th e ir use o f th e isla n d s and
breeding success, and is continuing a study o f
feeding ecology.
C ensusing a population o f birds which
winters on nearly 200 rem ote islands (m ostly
now uninhabited by m an) scattered from
C ounty K erry to Sutherland m ust present
certain p ro b lem s. T h e o n ly s a tisfa c to ry
m ethod is counting from the air. Aerial su r­
veys for goose counting were first undertaken
in B ritain on a re g u la r b asis in 1957.
A lthough the technique is well know n, there
are a num ber o f difficulties inherent in flying
off the west coast o f the British Isles. Airfields
with fuel are few and survey routes have to be
planned accordingly. The w eather, w hich
arrives there less well-heralded th an further
east in the country, often causes tiresom e
delays. T o these logistical item s m ust be
added the problem s o f locating and counting
the birds. Boyd (1968) gave a full account o f
the techniques involved and som e o f the
difficulties and pitfalls encountered. It is
sufficient here to state th a t a light aircraft is
used, flying at about 140 k m /h r and at
15 0 -20 0 m etres above the sea. O ne or two
observers are carried in addition to a pilotobserver. Photographs o f flocks are obtained
where practicable but are n o t relied on, as
visual counting by experienced observers has
been found to be as accu rate as and m ore
reliable than photographs, w hich m ust often
be taken in very p o o r light.
Largely because o f expense, aerial surveys
o f B arnacle Geese have been neither regular
nor frequent. Partial or com plete surveys
were carried out in 1957, 1959 (two), 1961,
1962, 1965, 1966 and 1973. Those in 1957
and 1965 were restricted to the Scottish part
o f the range and in M arch 1959 only Ireland
w as covered and then n o t com pletely. Boyd
(1968) gave the results for the Scottish range
o f the first six surveys b u t did not report on
the Irish figures in any detail. C ab o t & W est
(1973) reviewed the Irish results (though
excluding M arch 1959), in th e context o f the
study o f the birds on the Inishkeas. This paper
gives the full results o f the 1973 survey and
com pares them with the results o f all the
previous surveys.
B arnacle G eese know nothing o f boun­
daries between countries and draw no distinc­
tion between Ireland and Scotland. H ow ­
ever in this paper the tw o countries will
be separated if only because their current
shooting and conservation arrangem ents are
different, and future steps m ay be taken on a
national not international basis.
Aerial survey results
In the course o f the eight aerial surveys B ar­
nacle G eese have been found on a total o f 169
islands and (in a few cases) headlands. C abot
& W est (1973) list a further 23 Irish sites
w here B arnacle G eese have been recorded at
some tim e though none were present during
any o f the surveys. In som e o f the archi­
pelagos in both Ireland and Scotland the
geese alm ost certainly use all the suitable
islands at som e time although actual sightings
have not been recorded. This will be true, for
example, in the Sound o f H arris, between
H arris and N orth U ist, w here B arnacle Geese
139
140
M. A. Ogilvie an d H. B oyd
have been recorded from 20 islands during the
aerial surveys b u t could be expected on vir­
tually all the 5 0 -6 0 islands (the exact num ber
depends on definition) in the Sound.
A com plete tabulation o f the survey results
has been deposited at the Wildfowl T rust. In
any discussion o f the figures, however, and es­
pecially in m aking com parisons between the
years, it is m ore meaningful to group the
islands according to an, inevitably som ew hat
subjective, assessm ent o f how m uch, o r how
little, the geese move around during the
course o f a w inter. F o r example, whereas
there can be no justification for splitting the
Blasket Islands, C o. K erry, into the five con­
s titu e n t is la n d s , n o n e m o re th a n fo u r
kilom etres from the next and only tw o o f
w hich have held geese at the tim es o f the su r­
veys, it does seem right to treat them separate­
ly from the next nearest haunt, the M agheree
Islands, 43 kilom etres to the north-east.
T he m ap (Figure 1) show s the groupings,
while the survey results are given in T able 1.
T he m ajority o f the individual sites group
them selves conveniently but in som e areas
there m ay be a whole chain o f islands
stretching over 60 o r 70 kilometres. In these
cases an arb itra ry 10 km h as been chosen as
Figure 1. Map showing groupings of Barnacle Goose haunts. Numbering as in Table
1.
141
Barnacle Goose survey
Table 1. The numbers of Barnacle Geese Branta leucopsis counted during aerial surveys, 1957-1973
Figures in brackets represent interpolated means of other counts for that site or group. No inter­
polations have been attempted for the February 1957 and March 1959 censuses or for the in­
dividual sites or groups in Ireland in March 1965 (see text).
R eg io n
(see T a b le 4 )
N o . on
m ap
(F ig u re 1)
E a st C o a s t
K e r r y - C la r c
G a lw a y - S . M a y o
W . an d N . M a y o
Sligo D o n eg al
Islay
In n e r H eb rid es
In n e r H e b rid es
O u te r H e b rid es
N . a n d W . c o a s ts
N o . o f sites
w ith g eese in g ro u p
I
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
L a m b a y Is.
W ex fo rd S lobs
B laskets
M ag h ere e Is.
Illau n ea ro n
M u tto n Is.
M a c D a ra ’s Is.
H igh Is.
In ish b ro o n
In ish d alla
C lew B ay
In ishgallon
D uvillaun
Inish k e as
Inish k e era g h
K id Is.
L issadell
Inish d u ff
R a th lin
T o ra y la y d o n
In ish d o o ey
C lo n m a ss
G la sh e d y Is.
T O T A L IR E L A N D
1
1
2
2
1
1
1
8
1
6
3
1
4
2
4
6
5
2
1
5
8
1
4
69
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
Islay
T ro d d a y
B ro sd a le Is.
E n . M o r(K in ty re )
E n . M o r (Ju ra)
O ro n sa y
Soa
T re sh n ish
Tiree
M uck
B a rra
S o u n d o f B a rra
S o u th U ist
M onachs
S o u n d o f H a rris
T a ra n s a y
G ask e ir
S h ian ts
L. R o a g
L. E riso rt
Isay
A sc rib s
T ro d d a y
Longa
F o u ra
S u m m er Is.
A . C hleit
C h ro n a
R o in M o r
H o a n Is.
R a b b it Is.
TOTA L SCOTLAND
(excluding Islay)
TOTAL SCOTLAND
1
1
2
1
1
1
1
5
3
1
11
6
1
3
20
2
1
3
2
2
4
3
4
i
GRA N D TOTAL
169
1
6
2
4
2
2
3
F eb
1957
D ec
1959
M ar
1961
A pr
1962
M ar
1965
12
0
0
6
0
190
40
160
53
50
30
1200
10
240
363
0
10
90
2 10
0
107
2771
85
34
0
2 80
0
140
0
51
150
0
157
2300'
153
152
2 30
0
0
130
247
50
5
4164
0
0
90
265
0
213
0
86
85
0
23
2500'
188
76
304
35
(2 0 )
182
309
45
3
4424
(4 0 9 5 )
2800
0
140
0
10
0
0
299
25
0
49
86
110
480
174
15
110
29 0
0
0
130
0
60
56
0
73
37
172
21
(214)
(199)
2750
5500
18
107
14
4
0
0
470
3 80
0
142
452
2 50
5 19
599
120
10
214
0
0
140
122
108
15
0
0
33
100
64
180
179
4240
4800
0
124
44
0
230
0
3 90
4 84
2
171
415
0
8 60
49 8
7
70
317
0
32
39 5
204
47
20
11
57
0
9
0
24 4
135
4766
(8 3 0 0 )2
(3)
(76)
(67)
(6)
(51)
(17)
51 0
(301)
(5)
28 9
39 2
23
75 0
4 93
0
140
450
52
0
420
308
264
5
0
(74)
(26)
(92)
(58)
(214)
(199)
5285
M ar
1966
M ar
1973
20
0
60
320
0
411
0
90
0
40
156
2600'
40
42
3 70
18
0
2 62
195
80
14
4718
45
2
0
0
0
480
43
53
20
4
0
0
145
1980'
240
164
2 10
45
70
395
282
0
2 20
4398
0
0
106
40
40
160
0
90
1600
190
30
0
71
2327
3000
0
38
35
0
16
5
317
420
19
223
238
20 0
33 0
4 90
201
41
303
37
0
151
193
182
38
21
95
52
121
0
3766
100
M ar
1959
6766
2800'
8500
0
45
196
16
18
61
795
354
(5)
4 43
3 60
0
1035
575
120
122
483
19
6
©
oo
Skye
S ite o r
g ro u p ed sites
272
236
0
0
146
33
55
74
425
130
6579
15000
0
0
110
(6)
40
35
4 19
143
(5)
80
3 36
0
6 40
9 80
125
0
450
0
0
297
132
143
(22)
(5)
(74)
0
96
190
6
35 0
4684
5550
9740
9566
12396
15079
19684
8321
13904
13990
17680
19802
24 0 8 2
N o te s. !. W e h a v e follow ed C a b o t & W e st (1 9 7 3 ) in u sing g ro u n d c o u n ts o f geese o n th e In ish k e a s fo r th e la st f o u r Irish su rv e y s. T h e y w ere g e nerally m ade
w ith in a m o n th o f th e a e ria l cen su s, a n d th e ir in c re a se d a c c u ra c y o v er aerial c o u n ts is th o u g h t to o utw eigh th e d a n g e r o f m o v e m e n ts h a v in g ta k e n p lace
in th e interv al.
2. T h is in te rp o la te d figure fo r Islay is th e m ea n o f tw o g ro u n d c o u n ts m a d e o n th e island th a t w inter.
142
M. A. Ogilvie and H. Boyd
the dividing distance. This brings the num ber
o f grouped haunts to 23 in Ireland and 31 in
Scotland, a total o f 54. The table also shows
how m any individual sites go to m ake up each
group. The nam es used in the table are o f the
largest or m ost im p o rtan t site in each group, if
there is no convenient accepted geographical
nam e for the latter.
Som e attem pt has been m ade in Table 1 to
com pensate for gaps in the surveys. Some
Scottish haunts w ere om itted from the sur­
veys in 1959 (D ecem ber), 1965 and 1973, due
to lack o f time, or to bad w eather. By
averaging the existing counts for these haunts
and interpolating the average figure into each
survey a m ore realistic total is arrived at. Only
in 1965 is the added figure m ore than a few
hundreds and then only because an estim ated
total for Ireland (not covered th a t year) has
b een g iv e n . E s tim a te s h a v e n o t b een
attem pted for the first survey carried out in
each country (F eb ru ary 1957 in Scotland and
M arch 1959 in Ireland) which were to some
extent exploratory, and for which interpola­
tion is im practicable due to the lack o f antece­
dent counts from m ost sites.
Because the num ber o f geese present on
Islay com pletely dom inates the totals, a
separate total, excluding Islay, has also been
given for each survey. These show th a t there
was a virtual doubling o f the num bers o f geese
between D ecem ber 1959 and M arch 1966 at
a rate only slightly exceeded by w hat w as
happening on Islay. Between M arch 1966 and
M arch 1973, however, num bers aw ay from
Islay dropped slightly, back to the level of
M arch 1965, while the num bers on Islay n ear­
ly doubled again. Indeed, other counts on
Islay, both before and since the M arch 1973
count, have produced even high num bers, up
to 19,400. T here is not a great deal o f pattern
in the changes th a t have occurred at other
haunts in the 1966—1973 period though in the
13 haunts averaging over 250 geese, num bers
have declined at ten and increased at only
four. The big questions th a t need answering
are: to w hat extent have birds deserted other
haunts in favour o f Islay; and how m uch is
due to special factors operating at Islay
alone? It is doubtful w hether exact (or indeed
any) answ ers can be given but som e o f the
evidence can at least be examined.
O ur knowledge o f changes in farm ing and
other hum an uses, o r o f natural causes such
as plant succession, o r loss o f tu rf in storm s,
that might affect the num bers o f geese on the
rem o te isla n d s fre q u en te d by th em , is
fragm entary. O nly in one case is there an ob­
vious reason why B arnacle G eese have com ­
pletely deserted a locality. A rocket range was
constructed in 1961 on the m achair beside
Loch Bee, South U ist, and the flock o f up
to 250 B arnacle G eese th at used to w inter
there prom ptly, and n o t surprisingly, went
elsewhere. The next nearest h aunt to Loch
Bee is the M onach Islands off the w est coast,
where there w as an increase o f the right order
by the time o f the next survey. N um bers con­
tinued to increase on the M onachs up to April
1966. In D ecem ber 1966 the islands were
declared a N ational N atu re Reserve, prim ari­
ly for the geese. The latter appear to have
repaid this gesture by a large drop in num bers
by 1973. The islands are not w ardened and
rarely visited in the winter m onths and there
do not appear to be any reliable counts
between 1966 and 1973. O ther increases or
decreases can readily be found in Table 1 but
in no case are there easy answ ers to the ques­
tion of why the num bers have changed. An
alteration in the num ber o f shooting parties,
disturbance by fishermen, changes in the
num bers o f sheep being grazed, are all possi­
ble factors th at com e to mind, and for none of
them does any rem otely useful or precise in­
form ation exist.
T able 2a sets out the percentage o f in­
dividual sites counted in each survey which
actually held geese. These show an increase to
a peak in 1962, then a decline o f 6% by 1966
and a further decline o f 10% in 1973. The pic­
ture for the tw o countries is m uch the same.
The usage o f grouped sites (Table 2b) has
sh o w n m o re flu c tu a tio n th a n c h a n g e ;
although 1973 w as 9% below 1966 it was
only back to the level o f earlier years. The
drop from 1966 to 1973 w as m uch m ore
pronounced in Scotland th an in Ireland. Both
tables show a decrease between 1966 and
1973 th at parallels the overall decline in
num bers o f geese elsewhere th an on Islay,
reinforcing the suggestion th at the great in­
crease on Islay since 1966 has been at the
expense of other individual sites. F urther sur­
veys are needed to see w hether these losses
will becom e perm anent.
A nother possibility th at would lead to a
reduction in the num ber o f sites being used is
if the birds are changing their flocking habits.
A ny tendency to concentrate in fewer larger
flocks would have the sam e effect on site use.
A w ay from Islay, the geese occur in a great
m any very sm all flocks. Table 3 show s the
counts from the five com plete surveys broken
down by flock size and expressed as percen­
tages o f the total num ber o f flocks. N early
one-third o f all flocks were under 50 birds,
while only about a qu arter were over 250.
These figures exclude Islay. They have been
calculated for the grouped sites as show n in
Barnacle Goose survey
143
Table 2. The percentage use by Barnacle Geese Branta leucopsis of Individual and grouped sites,
1957—1973
(a) Use o f individual sites
N u m b e r o f sites u sed a t e a c h cen su s
T o ta l n u m b e r o f sites u sed , 1 9 5 7 -1 9 7 3
C o u n try
Ire la n d
S c o tla n d
T o ta l
T o ta l o f sites c o u n te d
in e a c h c e n su s
T o ta l N o . o f sites
used, 1 9 5 7 -1 9 7 3
Sep
1957
M ar
1959
D ec
1959
69
102
171
32
42
37
53
37
57
52
32
40
49
97
44
164
169
52
M ar
1961
A pr
1962
x
M ar
1965
M ar
1966
M ar
1973
55
55
55
48
49
49
43
56
164
69
167
160
37
39
(b) Use o f grouped sites
N in n i v i ' n i ' ¿ r o u p e d s ite s u s e d a t e a c h c c n s u s
T o t a l n u m b e r o f g r o u p e d s it e s u s e d . 1 9 5 7
Irelan d
S c o tla n d
T o ta l
T o ta l o f g ro u p e d sites
c o u n te d in e a c h c e n su s
T o ta l N o . o f g ro u p e d
sites u sed, 1 9 5 7 -1 9 7 3
S ep
1957
23
31
54
86
86
29
Table 1. If the actual counts recorded for each
individual site are used in place o f class
frequencies, we find th at ju s t over 50% o f
flocks are under 50. T hough the proportion o f
flocks over 250 has risen from 14% in 1959
and 19% in 1961 to 37% in 1966 and 32%
in 1973, no statistically significant changes
in relative frequency o f flock sizes have
occurred.
M ean flock size is also show n in Table 3.
There w as virtually no change between 1966
and 1973 but both are considerably higher
than the three earlier years.
R egional changes
If overall changes in use o f sites and flock size
are not easy to find, changes in regional dis­
tribution are a little m ore obvious. The d ata
from Table 1 have been lum ped into five Irish
1973t
M ar
1959
D ec
1959
M ar
1961
A pr
1962
M ar
1965
M ar
1966
85
85
76
69
72
71
77
75
71
74
73
81
81
76
87
82
74
73
73
13
50
52
52
16
51
49
and five Scottish regional groupings. The
dividing lines are show n in Figure 1. Islay
is considered on its own. O therw ise the
groupings are by fairly n atural boundaries
with distances in excess o f 30 km between the
nearest haunts in adjacent regions. The
resulting regional totals are show n in Table 4,
while Figure 2 uses the sam e d ata expressed
as percentages o f the earliest survey total for
each region.
A p art from the dom inating position of
Islay, the other regions show some interesting
changes. Excluding the hardly represented
east coast o f Ireland, num bers in the other
eight regions fluctuated som ew hat between
the early surveys b u t all showed a rise
between 1962 and 1966 so th a t by the latter
survey all were above their starting level, in
some cases considerably so. This trend was
noticeably reversed between 1966 and 1973,
six regions dropping in num bers and two
Table 3. Percentage distribution of flock sizes per grouped sites of Barnacle Geese Branta leucopsis,
1957—1973. The figures exclude Islay.
Flock size
Dec
1959
Mar
1961
Apr
1962
Mar
1966
Mar
1973
All
1-50
51-100
101-250
251-500
over 500
No. of flocks
Mean flock size
37
17
32
11
3
35
146
23
11
47
11
8
38
222
31
16
24
24
5
38
187
29
15
19
27
10
41
250
26
11
31
23
9
35
252
30
14
30
19
7
187
235
M. A . Ogilvie and H. Boyd
lg below their datum ,
is notew orthy and rath er encouraging
the furthest p a rt o f the range, K errye, has show n an increase, albeit a small
If the southernm ost tw o Irish regions are
:d together there has been a slight overall
increase, though with a rath er large drop from
the peak o f 1966. Sligo—D onegal gained from
1966 to 1973 and the central p a rt o f the Irish
range declined. H owever, it does appear th at
despite a w ithdraw al from the W exford Slobs
during the 1950s, the population is not con-
500
450
400
350
300-
250
200
150'
100
•
50-
0
.9 5 7 '
'
195-5
'
1 9 6 1 ’ 19 6 ¿
'
'
1965' 1966
'
'
'
197?
Figi e 2. Regional totals of Barnacle Geese expressed as percentages of earliest survey total for each
n.
145
Barnacle Goose survey
Table 4. Regional distribution o f Barnacle Geese Branta leucopsis, 1957—1973
Region
Feb
1957
E. coast
Kerry-Clare
Galway—S. Mayo
W. and N. Mayo
Sligo—Donegal
Islay
Inner Hebrides
Outer Hebrides
Skye
W. and N. coasts
3000
850
2063
526
327'
Total
6166'
Mar
1959
346
1880'
1011
2771'
Dec
1959
Mar
1961
Apr
1962
18
493
1480
780
2800
474
1314
190
772
399
341
2762
662
5500
993
2306
370
571
355^
384 1
2787 [
89 8 /
4800
1274
2370
646
476
8321
13904
13990
Mar
1966
Mar
1973
mean
8300
1036
2589
992
668
( 400
I 541
\ 2838
I 939
8500
1670
3163
888
863
47
480
120
2529
1222
15000
758
2611
572
743
47
330
371
2479
900
6843
1008
2343
598
682
17680
19802
24082
16297
Mar
1965
40Q5
1 Incomplete, and excluded from calculation of means.
tra d in g its range in response to the o pportuni­
ty o f exploiting o f apparently b etter wintering
conditions further north on Islay.
N um bers in Ireland as a w hole have not
changed very m uch over the period 1961 to
1973 after an initial increase from the first
com plete survey in N ovem ber 1959. The total
fo r S co tlan d , ex clu d in g Isla y , w as very
sim ilar to th at for Ireland for the N ovem ber
1959, 1961 and 1963 surveys, leaped ahead
in 1966 but dropped back to only ju s t above
the Irish figure in 1973. The recent decline
was fairly evenly spread between all four
regions, with the largest d ro p both p ro p o r­
tio n a te ly a n d a b s o lu te ly in th e In n e r
H ebrides, the area nearest to Islay. The area
further aw ay from Islay, the w est and north
coasts o f the m ainland, show ed the least
decline.
T able 5 shows the percentage distribution of
the geese betw een th e regions for each com ­
plete survey. A lthough Islay has alw ays been
the largest single com ponent o f the whole, it is
only since 1966 th a t it has becom e com pletely
dom inating, holding at the time o f the 1973
census no less th an 62% o f the entire p opula­
tion. The other regions have declined acco r­
dingly, with Ireland and th e rest o f Scotland,
form erly holding roughly one-third apiece,
now dow n to a b o u t one-fifth.
Discussion
T here is no doubt th at the censuses since 1957
o f G reenland B arnacle G eese wintering in the
British Isles have revealed a substantial in­
crease in total num bers. H igher counts on
Islay since the last com plete census (the latest
being 19,400 in N ovem ber 1974) suggest th a t
the overall increase is being m aintained. W hat
is less satisfactory is the continuing concen­
tration o f the geese on to Islay. D espite the
Table 5. Percentage distribution of Barnacle Geese Branta leucopsis by regions, 1959-1973.
Region
Dec
1959
Mar
1961
Apr
1962
Mar
1966
Mar
1973
mean
E. coast
Kerry-Clare
Galway—S. Mayo
W. and N. Mayo
Sligo-Donegal
Islay
Inner Hebrides
Outer Hebrides
Skye
W. and N. coasts
Ireland
Scotland, excl. Islay
0
<1
6
18
9
34
6
16
2
9
0
3
2
20
5
40
7
16
3
4
0
3
3
20
6
34
9
17
5
3
0
2
3
14
5
43
8
16
5
4
<1
2
2
17
6
43
6
15
4
5
33
30
32
24
33
30
34
33
<1
2
1
10
5
62
4
11
2
3
18
20
27
30
146
M. A. Ogilvie and H. Boyd
m itigating discovery th a t the range is not also
contracting, it m ust be a m atter for concern
th at so large a proportion o f a relatively small
population o f birds is to be found in ju s t one
haunt. A part from the danger o f some natural
or m an-induced calam ity destroying the birds
or their habitat, there is an increasing am ount
o f conflict w ith agriculture on the island.
T he m ajo r landow ners are on the whole
favourably disposed to w ard s the geese but
som e o f their ten an t farm ers are un d erstan ­
dably getting m ore and m ore worried. Some
small-scale experim ents to assess the effects of
the grazing by the geese are under w ay and
there has been an increase in the am ount of
deliberate scaring o n a few farm s. C ontrol
m easures, though o f an unspecified nature,
have been advocated, presenting the co nserva­
tion bodies, both statu to ry and non-statutory,
with the m ajor problem o f reconciling the in­
terests o f farm ing w ith the wellbeing o f such an
im portant flock o f geese. A detailed account of
the num bers o f B arnacle G eese on Islay in the
last tw enty years is in preparation, together
w ith an analysis o f the annual breeding data.
A s has earlier been stated, we have lam en­
tably little inform ation th a t can help us
answ er the question o f w hy the B arnacle
G eese are concentrating on Islay. A p art from
possible changes in farm ing practice already
m entioned, there are the potential effects o f
shooting. The species w as given full p rotec­
tion in Ireland in 1962, but few o f the birds in
th a t country were ever accessible to heavy
shooting pressure and it seems unlikely th a t
the change in the law has had a significant
effect. A fter being given full protection in
Scotland in the 1954 P rotection o f Birds A ct,
a relaxation w as m ade the following year
allowing a tw o-m onth shooting season from
1st D ecem ber to 3 1st Jan u ary on islands to
the west o f longitude 5°W. This effectively
covers all haunts o f the G reenland B arnacle
G oose in Scotland except for a handful on the
north coast o f Sutherland. A gain it seems
doubtful w hether there has been any m ajor
change in the am o u n t o f shooting, or at any
rate sufficient to pro d u ce the concentration o f
birds on Islay. Shooting on th a t island is not
heavy, being controlled by the few large
estates.
If we cannot explain w hat has happened in
the past, perhaps it is still pertinent to look
into the future. It seem s clear th a t although
there is probably still room for further in­
crease on Islay, scaring and shooting there
will also increase, leading to a levelling off o f
the num bers if not an actual decline. W hat is
therefore needed w ould seem to be som e w ay
o f im proving the situation for the geese
elsewhere th an on Islay, to encourage the
birds to m aintain their num bers on the m any
other haunts, o r better still to increase them . It
is easier to say this than to decide w hat
m easures could be taken but they might in­
clude statutory protection on the m ore im por­
tan t Scottish haunts, though the effect o f
declaring the M onachs a N atio n al N ature
Reserve is disappointing, coupled with the en­
couragem ent o f continued grazing o f the
islands by sheep to help m aintain suitable
feeding sw ards for the geese. A dditionally,
future oil exploration off w estern Scotland
and any associated industrialization m ust be
carefully w atched to minimize adverse effects
on the geese.
U nfortunately the kinds o f research th a t
w ould be needed to discover som e o f the basic
facts about w hy the geese are m oving to Islay
and how to persuade them to m ove aw ay
again would be very expensive. Even the
minim um m onitoring o f a com plete census
has only been afforded at ever longer inter­
vals. R egular co u n ts on Islay are relatively
cheap and are continuing, b u t the census
results show clearly th a t the relationship
between the Islay situation and w hat is
happening over the rest o f the range is a
steadily changing one and predictions o f the
latter based on the form er m ust be regarded
with due care. It is to be hoped th a t if further
m ajor changes take place in the num bers of
geese on Islay, in w hichever direction, the
consequent need to look again at the overall
picture will be recognized.
Acknowledgements
The censuses were carried out while one or both of
the authors were employed by the Wildfowl Trust
and funded by grants or contracts with the Nature
Conservancy Council and the Natural Environ­
ment Research Council. The 1973 census was ad­
ditionally supported by a grant from the Irish
Department of Lands.
We cannot overemphasize the part played by the
pilots in these aerial censuses. Dr S. K. Eltringham
and Mr A. Wingnall flew the aircraft in 1958 and
1959, but it is to Mr J. D. H. Radford that the prin­
cipal th ank s are due p articu larly for his
simultaneous application of the skills of piloting the
aircraft, counting the geese and photographing
them, all done in flying conditions that were often
less than perfect. Dr D. B. Cabot acted as an
observer for one of the Hebridean and several of
the Irish surveys and Mr O. J. Merne for one of the
latter.
Barnacle Goose survey
Sum m ary
Aerial censuses of the Greenland population of the
Barnacle Goose Branta leucopsis wintering mostly
on islands of the west and north coasts of Ireland
and Scotland revealed an increase from 8,321 in
December 1959 to 24,100 in March 1973.
147
Simultaneously the proportion o f the total
wintering on the main haunt o f Islay has risen from
34% to 62%. Changes in the use of sites and in the
size of flocks are discussed in relation to the in­
creasing importance of Islay. The conservation im­
plications of this latter factor are reviewed.
References
Boyd, H. 1964. Barnacle Geese caught in Dumfriesshire in February 1963. Wildfowl Trust Ann. Rep. 15:
75-76.
Boyd, H. 1968. Barnacle Geese in the west of Scotland, 1957-67. Wildfowl 19: 96-107.
Cabot, D. & West, B. 1973. Population dynamics of Barnacle Geese, Branta leucopsis, in Ireland. Proc.
Roy. Irish Acad. Vol. 73, Sec. B: 415—43.
Larsen, T. & Norderhaug, M. 1964. Resultater av kvitkinngasmerkinger pa Svalbard. Sterna 6: 153-68.
Ogilvie, M. A. 1970. The status of wild geese in Britain and Ireland. Pp. 249-57 in The New Wildfowler in
the 1970’s, ed. N. M. Sedgwick et al. London: Barrie and Jenkin.
Owen, N. & Campbell, C. R. G. 1974. Recent studies on Barnacle Geese at Caerlaverock. Scot. Birds, 8:
181-93.
M. A. Ogilvie, Wildfowl Trust, Slimbridge, Gloucester, GL2 7BT, England.
H. Boyd, Canadian Wildlife Service, Eastern Region, 2721 Highway 31, Ottawa, Ontario, K1A OH3,
Canada.
Plumed or Eyton’s Whistling Ducks Dendrocygna eytoni at Slimbridge (Joe Blossom).