To the Island in these first few weeks of spring
there had come, from the surrounding seas and from the Atlantic
ocean, from lands and continents to the south, from the
neighbouring mainland of Britain, some hundreds of thousands of
birds. Of this multitude many had passed on towards their breeding
grounds elsewhere, in Britain and in Ireland, in Iceland, Greenland
and Scandinavia; but we estimated that nearly two hundred thousand
birds - more than ninety-one thousand pairs - remained on Skomer's
seven hundred and twenty acres to breed. By far the most of these
were the seabirds, and yet, if one stood on the highest rock on the
island, close to the house, one might scan the plateau of the
island in vain, looking for this great throng. It was only at night
that the shearwaters could be seen here in their thousands, sitting
outside the burrows on the turf in all the drier parts of the
island. But by day only the lesser black- backed gulls could be
seen in any numbers, for the herring gulls were mostly near the
cliffs, or on the cliffs, and the great black-backs were dotted
about on high points of the rocks here and there. But the cliffs
were noisy all day with the crowded jostling birds: the puffins,
most numerous of all, and outnumbering all the other birds on the
island, were along the cliff-tops, where they had their burrows,
and below them were the dainty screaming kittiwakes on their
isolated ledges, and the guillemots and razorbills packed tightly
along the more open, long rock-shelves.
The surface of the island plateau, apart from the
colonies of lesser black-backs, was scarcely more thickly populated
than similar clifftop moorland on remote parts of the mainland
coast, and the birds breeding there were much the same. Of the
thirty-six species breeding on the island, eleven were seabirds
properly so-called: the four gulls, three auks, Manx shearwater and
storm-petrel, cormorant and shag. The other twenty-five species
totalled rather less than two hundred and fifty pairs between them,
and thus provided an almost insignificant proportion of the whole
population, for all their variety.
Rock-pipits
These 'land-birds' included two species, the
rock-pipit and the oyster-catcher which have, perhaps, as much
claim to be called seabirds as any, except that neither of them
possesses webbed feet, and neither of them normally swims, though
the oyster-catcher can swim well enough on occasion. Both these
birds forage much at the edge of the sea, the rock-pipit among the
spray-splashed rocks and crevices, and among the wrack left by the
ebbing tide, and the oyster- catcher also among the weed, where it
knocks limpets and other shell-fish off the rocks with a sharp blow
of its powerful bill. But the oystercatchers live all over the
island - there were thirty-six pairs of them and probably on
Skomer, as on the much smaller island of Skokholm, those in the
centre of the island seldom or never went to the sea's edge for
their food, but found all they needed in the marshy ground in the
centre of the plateau. The rock- pipits on the other hand confined
themselves to the cliffs during the breeding-season, and there were
about thirty pairs of them more or less evenly distributed round
the perimeter of the island. Only after the young were fledged
would we see them on top of the island, trespassing on to the
ground occupied throughout the summer, and indeed throughout the
year, by the meadow- pipits, of which about sixty pairs nested
among bracken and heather. These three species were the commonest
of the land-birds, and between them were spread over the whole
island. During the breeding season the two pipits seldom trespassed
on each other's regions of the island: the rock-pipits remained on
the cliffs, while the meadow-pipits shared the turf of the island
with the wheatears. Here too there was some division between the
habitats, for the wheatears frequented the shorter rabbit- grazed
turf, and the stone walls, in which, as well as in the rabbit
burrows, they made their nests, but the meadow-pipits tended to
forage more often among the taller grasses and in the belts of
heather and bracken. No hard- and-fast line could, of course, be
drawn between these two habitats, and wheatears were often to be
seen on tumps of dry heather, and meadow-pipits on the walls; but
for all that there was some tendency to keep apart in the way
described.
Larks and Wagtails
Closely related to the pipits are the larks and
wagtails, but of these there were only three pairs of skylarks, and
a single pair of pied wagtails. The wagtails raised two broods in
one of the ruined outbuildings, and were often to be seen fly-
catching on the roof of the house. There was also a pair of
pied wagtails on Skokholm and one day we caught in the trap by the
house a chick which had been bred on Skokholm a few weeks earlier.
This was the only record of bird traffic between the two islands
which we obtained during this season, though since 1946 there have
been a few recoveries of seabirds marked on Skomer and found on
Skokholm. The skylarks sang over the island, as they sing every
year over Skokholm, and they bred near the marshy centre of the
island.
Dunnocks, Blackbirds and
Whitethroats
There, where the stream flowed out of the pond,
was a tangle of brambles, and some other bushes further down this
stream: in these dunnocks and blackbirds and whitethroats-the only
warbler to breed on the island in 1946 - were to be found. There
were about five pairs of whitethroats, two pairs of blackbirds, and
one solitary pair of dunnocks. Before the war dunnocks used to
breed regularly on Skokholm, sometimes as many as seven pairs, and
their cheerful little song was almost always to be heard from the
bracken near the big trap. Now, since 1940, they have not bred and
in 1946 and 1947 they were not even seen on the island. These small
isolated populations are liable to be wiped out quite suddenly,
after a bad season, and it may then be some years before a new
colony is established. In 1948 a dunnock was seen again on
Skokholm, and this may be the forerunner of a new colony. The
blackbird also used to breed on Skokholm, but has not done so since
1935, though it is a regular visitor outside the breeding season,
and there seems no reason for its ceasing to breed.
Wrens
Another bird which visits Skokholm regularly in
winter, but which has never yet been known to breed, is the wren:
but on Skomer we had some thirteen pairs, mostly about the cliffs,
or the ivy- and honeysuckle-covered outcrops above the cliffs.
Wrens are found breeding on most islands, even on the remotest
groups, where, as on St. Kilda, local races may develop in
centuries of isolation. Skomer is of course too near the mainland
for any difference to be noticeable among the island wrens, which
no doubt receive recruits from the mainland each autumn. But why
they never stay to breed on Skokholm remains a mystery.
Jackdaws, Crows and Choughs
Not less strange is the absence of jackdaws from
Skokholm, for they are always to be seen about the cliffs of Skomer
where about twenty pairs bred in old rabbit and puffin burrows made
in the loose earth at the cliff-tops. About the cliffs three other
members of the crow family were to be found throughout the summer:
three pairs of ravens, eighteen pairs of carrion-crows, and two or
possibly three pairs of choughs. The ravens nest, very early in the
year, in the same inaccessible sites year after year, and they are
to be seen on almost all the islands, even on remote Grassholm. The
carrion-crows also nest on the cliffs, in default of trees, and
make a great harvest of the eggs of razorbill, guillemot and gulls
- also of oyster-catcher or any other bird that leaves its eggs
briefly unguarded. (But the oyster-catcher is very bold and
effective in the defence of its nest, and suffers far less than the
bewildered and hopelessly inefficient guillemots.) The choughs were
most elusive, but someone usually saw them on most days - often six
of them together. They breed for preference within some high cave
or recess, where the nest is protected from the weather and from
sight, and they come up on to the fine turf at the top of the cliff
to probe for insects with their slender curved red bills. It has
been suggested that the spread of jackdaws has led to a decline in
the number of choughs breeding about our coasts, and certainly they
have declined in the past fifty or sixty years, though of late
protection has enabled this most handsome and svelte of birds to
hold its own along the coasts of Pembrokeshire. The case against
the jackdaw is not proven: the case against the egg-collector on
the other hand is all too clear. Perhaps one day the buoyant flight
of the chough swooping and playing in the currents of air above the
cliffs, and the cheerful squealing call will again be familiar to
many, and at least the visitors to the Pembrokeshire National Park
may have some chance of enjoying them. B. H. Ryves, studying the
chough in Cornwall, has found that there are many non-breeding
adults present in the nesting season. The behaviour of the six
adults on Skomer suggested to us that they were nonbreeders. At
least no mating or nesting activities were certainly
recorded.
Buzzards and Peregrines
The buzzards also bred about the cliffs, and it was a magnificent
sight to see sometimes as many as fifteen of these great birds
soaring together towards the summer sky. Seven pairs bred on the
island, but others came over at times from the mainland, as the
presence of the remains of a mole in the cast of a buzzard on
Middleholm proved. For the most part they lived on the rabbits of
the island, though they no doubt took some small birds, mice and
voles, and perhaps frogs, beetles and grasshoppers. The whole
island was theirs, though they made their nests in the safety of
the cliffs.
Above the screaming, growling, groaning proletariat of sea- fowl on
the Wick a pair of peregrines had their eyrie, and when not
stooping after puffin or razorbill, jackdaw or meadow-pipit they
would stand motionless for hours, surveying the multitudinous life
of the cliff with cold indifference. We seldom saw them over the
centre of the island: the cliffs provided all their needs, for they
did not need to prey on the small flightless creatures such as
voles, shrews and lizards which the slow buzzards and kestrels must
content themselves with. Sometimes no doubt the peregrines would
fly across to Skokholm, and perhaps they brought back from there a
puffin, whose leg, with a ring put on on Skokholm, we found one day
at the foot of a cliff. The peregrines were watched from a hide. On
June 8th one parent brought a ringed puffin to the nest, and tore
off the leg with the ring. This tough morsel was offered to the
chicks which refused it, whereupon the adult swallowed leg, ring
and claw. The eyrie was littered with the remains of rabbits,
puffins and shearwaters; this pair seemed to feed more than usual
on prey taken on the ground - it is almost certain that the
shearwaters would be taken as they rested on the ground, probably
early in the morning. R. M. L. in fact surprised one of the adults
feeding on a freshly killed shearwater dragged from under a slab of
rock where, judging by the litter of feathers there, it had been
first killed. When James Fisher climbed down to the eyrie on June
2nd to ring the two eyasses he found the remains of eleven
shearwaters and two puffins. Joan Keighley saw a peregrine on
August 10th feeding on a freshly killed kestrel, which she brought
into the house for identification; it appeared to be an immature
bird, quite probably not expert enough on the wing to escape a
determined peregrine.
Short-eared owls
The short-eared owls nested in the bracken near
the north stream. In April the striking 'song-flight' was watched.
It usually took place in the morning, but was recorded several
times in the evening also. One bird would rise until it was
estimated to be as much as seven hundred feet up (other estimates
on various occasions varied between two and five hundred feet). It
would circle, then suddenly clap its wings several times beneath
its body, at once falling vertically; the clap of the wings was
likened to a ratchet by one watcher. Usually the bird rose again,
circled, clapped its wings again, then uttered the hooting
'boo-boo- boo' as many as twelve times in succession. The mate of
the displaying bird meanwhile remained below actively quartering
the ground from a low level. Mating frequently followed the return
of the aerial exhibitionist to earth, even when in May the pair
were known to have well-grown young. We did not find the eggs, but
but the young birds - three of them - were estimated to be three
weeks old on May 19th, when they were ringed. This is very early,
and places egg- laying at the end of March, a month before the
usual time in Britain. The three young owls were killed by gulls as
soon as they left the nest and before they were able to fly; they
had probably blundered into the nesting territory of the lesser
black-backed gulls in the same area of bracken. Early in June the
adults, deprived of their brood, resumed display and song-flight
for about a week, but were much interfered with by the gulls which
attacked each soaring owl as it circled over their nesting
colonies.
We found no second nest of this owl, although in good vole years
this species will rear a second brood. The short-eared owls on
Skomer lived mainly on the Skomer voles and the wood- or longtailed
field-mice; it would be interesting to discover if the numbers of
this owl fluctuate with fluctuations in the numbers of the Skomer
voles, as they do on the mainland with the numbers of the mainland
vole, and, especially, on the Continent. It seems likely that at
one time this happened on Skomer also, for there are records of as
many as seven pairs of short-eared owls on Skomer about fifty years
ago, although in 1946 there was only one pair. It is certain,
however, that with the great increase of the breeding gulls, the
numbers of the island vole are kept down to a fairly low level,
since the gulls occupy so much of the same ground as the voles, and
also the voles are partly diurnal, affording the diurnal gulls many
opportunities of preying upon them. There are no recent records of
more than one pair of short-eared owls breeding on Skomer. When the
gulls have left the island in late autumn and winter, barn owls
take up residence on Skomer and may remain late into the spring
(April 1946; May 1947); they have sometimes bred there - in 1897
Drane found a pair breeding in a small cave on the Mew Stone, a
most improbable place to find this owl, one would have supposed,
among the cormorants and gulls.
Drane, quoted above, mentions the storm-petrel killed at night by,
as he seems to suggest, an owl of some kind. The short-eared owls
of Skomer sometimes visited Skokholm: to an owl which soared so
well this was only a short journey, two miles across the sea to the
lower island plateau so plainly to be seen from Skomer. One day a
visitor to Skokholm picked up a pellet from the ground beside a
roosting short-eared owl which he disturbed. This pellet contained
the remains of a stormpetrel, a prey never before authentically
recorded for the short- eared owl. We had had much
trouble before the war with little owls on Skokholm, and in the end
we had had to destroy or deport the owls in order to preserve the
petrels. On Skomer there seem to be fewer storm-petrels than in
Drane's time, probably now not more than thirty pairs, and these
were persecuted by the little owls, as we shall describe in the
chapter on petrels.
Little Owls
The little owl is a new arrival in Pembrokeshire,
first breeding in 1920, and was numerous on the islands seven years
later. One pair (possibly two) bred in 1946. Though only one nest
was found, and the young ones in this did not survive, a juvenile
bird just able to fly was seen on July 20th - but this may possibly
have flown over Jack Sound from the mainland. The curious feature
of the nesting of this pair of little owls was the finding, on June
17th, of one owlet dead and the other dying with a damaged wing;
the nest was under a huge slab of rock on the south cliffs, and in
a recess at the back, beyond the owlets' home, a puffin was
brooding. A puffin, we believe, is more than a match for a grown
little owl, but we never discovered whether or not it had attacked
the young owls.
Curlews and Lapwings
On the marsh, not far from the house, there were
curlew and lapwing breeding: the latter we had expected, for they
breed regularly on Skokholm, but the finding of five pairs of
curlew on Skomer was a most delightful surprise, for surely there
is no lovelier sound made by birds than the wild, thrilling song of
the curlew as he flies above his mate, quickly shivering his wings
in time to the bubbling cry. That song had been the favourite of
one of the finest men who had ever been to Skokholm, but, after
winning the D.S.O. and the M.C. (twice over) Geoffrey had been
killed in the Mediterranean at the age of twenty-six. And so he
could not share in this new pioneering on the islands, nor lie and
listen to the curlews with us any more.
One pair of curlew, with a nest near the south
pond, had seven eggs to incubate. This nest was found on May 5th,
and closely watched from a distance on several occasions, but only
two birds were ever seen near the nest, and of these one was
observed to sit for varying periods. On May 27th one egg was
chipped and the beak showing through. On the 29th two chicks had
hatched out and were successfully piloted away to food and cover by
the parents, which then abandoned the five remaining eggs, which
were found to be addled.
Oyster-catchers
But of all the land-birds on Skomer the most
conspicuous in voice and in plumage was the oyster-catcher or
sea-pie (as it used to be called, with more aptness) - the bird
sacred in Celtic legend to St. Bride, over whose bay we looked out
every day. In 1939 we had begun a study of this striking bird on
Skokholm (Buxton 1939) but the war had interrupted this, and now on
Skomer we proposed to continue this study so far as we might.
Skomer is less well suited to the oystercatcher than Skokholm,
which has a larger number of pairs breeding. The reason for this
may be the greater density of bramble and tangled vegetation on
Skomer, for the oyster- catcher likes to run up to its nest and
also likes some sort of hillock from which to keep watch near at
hand. This season we gathered what data we could about the
incubation period of the species, but these eventually proved less
precise than we required and this part of the work was continued
with great patience and skill by Joan Keighley on Skokholm in 1947
(Keighley and Buxton, 1948). In 1946 the first clutch found on
Skomer was already complete on April 28th and, since the incubation
period is normally slightly under twenty-six days, the first chicks
must have hatched not later than May 24th - a little earlier than
we have found to be usual on Skokholm. The last chick hatched on
July 19th, much later than any of which we have record from
Skokholm, but probably the clutch here was a replacement of eggs
taken by gulls or crows. (In 1946 on both islands and in 1947 on
Skokholm over 30 per cent. of the eggs were lost in this
way.)
Late in the summer, when the young birds,
distinguishable by their browner plumage and dull bills, are on the
wing, the oyster-catchers tend to congregate together, when they
are not feeding, on some rock or boulder - on Skomer a favourite
place was on the west side of South Haven. Here they stand and
snooze peacefully side by side, and the excited piping is seldom
heard after July is out. With the moult they get a white collar
about the neck, and we tried to discover, by counting the
proportion of birds with this collar, how soon the winter plumage
was assumed. To our surprise the proportion seemed to remain about
the same throughout the last two months of our stay on the island,
and this probably suggests a constant-shift in the population
seemed to remain about the same throughout the last two months of
our stay on the island. And indeed, since then, we have had a
number of oyster-catchers from Skokholm recovered in France,
showing that there is a rather more marked migration in autumn than
had been supposed. But our studies of this bird continue and are
likely to continue for some years to come.
The chicks may take as much as three days to
emerge from the egg after the shell has first been chipped. As soon
as they are dry they run from the nest, and thereafter the
territory of the parents is mobile, centred upon the chicks, which,
in the weeks that elapse before they are able to fly, may run
hundreds of yards from the nest.
The elaborate strange 'piping' ceremony of the
oyster- catcher which is used in many different situations has been
too often and too well described for us to describe it again. It is
perhaps enough to say that the familiar vibrant trilling which
accompanies this performance was a frequent but always delightful
sound, by day and by night, during the first part of the summer. It
is a communal performance and the voices of the piping birds blend
perfectly as they run along, he and open bill pointing to the
ground; and (as Selous said) they have an absent- minded
appearance, as if they were wholly absorbed in what they are doing,
as, no doubt, they are.
Mallards and Moorhens
On the north pond, or in the flags and sedge
beside it there were four pairs of mallard and two most elusive
pairs of moorhens. It was strange that these birds should be so
wild and skulking here, like waterrails, when they are so tame and
confiding on the concreted pools of most of our great cities, but
it was so, and this problem of tameness is one which has only
recently received the attention it deserves.
Linnets and Starlings
Two other very familiar species bred on the
island, at either end of it - about four pairs of linnets on the
Neck, and at the most seaward point of the island an adventurous
pair of starlings. This may well have been the first occasion on
which starlings bred, though linnets were known to be more or less
regular on Skomer, for it was only in 1940 that starlings first
bred, in the eaves of a shed belonging to the lighthouse, on
Skokholm. The starling is one of the most successful birds of
recent times and it has spread considerably within the last century
- in Pembrokeshire more recently still, for when Mathew wrote his
account of the birds of Pembrokeshire in 1894 it was still quite
scarce as a breeding bird. It is so vulgar and plebeian a creature
with its cockney whistlings and mutter that one is not nowadays
surprised to find it anywhere, and after all it is a cheerful bird
and, in a good light, a handsome one. The difficulties of
colonising an island full of predatory birds were too much for this
solitary pair, which nested within sight of the peregrines' eyrie.
The pair were busy at the rock cranny near the Basin, where a
tell-tale splash of white mutings marked a nest inaccessible to
human climbers, until May 19th, after which only one adult was
recorded. The widow, or widower, disappeared after June 6th, and no
young birds were fledged. It may be significant that a migrating
merlin was seen near the Basin on May 20th, but peregrine or owl
might have been responsible, too. We saw no more starlings until
the first pack of twenty-nine brown- plumaged juveniles arrived
from the mainland on June 22nd, the forerunners of the autumn
migration.
Pheasants
One other bird remains, the pheasant, though
whether it bred on the island or not we never discovered. There
were a cock and three hens, but no chicks or young birds were seen.
Some of us rather expected that the skipper's rabbit- snares, set
in paths known to be frequented by the cock pheasant and his harem,
would catch one. But instead the snares unexpectedly caught once an
oyster- catcher and once (August 9th) an adult raven.
Presumably the pheasant was introduced on to the
island at some date, though we have seen pheasants flying across
Jack Sound to the mainland, and it might perhaps have colonised the
island without human assistance. Skomer is so utterly unlike the
usual haunt of the pheasant that it always seemed odd to see them
on the island, where there were no neatly ploughed land, no
stubbles, no carefully preserved coverts. But the pheasant is a
hardy bird, and it seems well able to thrive even in such
conditions as Skomer offers, and if it chose to desert the island
it is able to do so.