It is not uncommon for pleasure boaters and fishermen to witness
long lines of these birds flying in single file low over the sea,
with occasional undulations as if rising to avoid some invisible
obstacle in the flight path.
I stirred from my light sleep bathed in sweat, the strange acrid
smell in the air filling my nostrils. The wind had died in the
night and the humidity had risen. We thought that we had got away
with it this time, fooled by the pleasant coolness of the evening
before. However, this was October on the Hawar Islands in the
Arabian Gulf and at this time of year the humidity makes for discomfort
which would befit any of the world’s rainforests.
The continuous throaty burping linked the stench to its owner.
We had set up camp on the periphery of one of the world’s largest
Socotra Cormorant colonies, there to photograph the 50,000 or
more birds which congregate on South Sowad Island to breed in
October each year.
From the tent flap we peered out across the low, flat, sandy scrub
covered island into the mist hanging eerily over the mass of jostling
black shapes stretching to the horizon. The sun had not yet risen
as it was only 5 am, but it was evident that many birds had arrived
in the night since the colony was almost twice the size of the
previous evening. Most of the new arrivals were loafing around
the edge of the main nesting areas and soon took flight as the
large orange sun peered over the horizon. Many of the birds stopped
initially to bathe about a hundred metres offshore in the shallow
waters surrounding South Sowad Island.
The Socotra Cormorant is a little-studied species which has a
very restricted world distribution. How the name originated seems
to be something of a mystery as, to our knowledge, there has not
been any record of a breeding colony of Socotra Cormorants on
the island of Socotra in the Arabian Sea. There are two main breeding
populations. One on various islands of the Arabian Gulf which
mostly nest in the winter months (Ed:-see accompanying article
concerning international research on Socotra cormorants). Many
of these sites are being subjected to increasing human disturbance.
A second population breeds during the summer on Al Hasikiya Island
off the coast of Southern Oman.
The Socotra Cormorant is mainly a sedentary species but large
movements of unknown significance are made within the breeding
range. It is not uncommon for pleasure boaters and fishermen to
witness long lines of these birds flying in single file low over
the sea, with occasional undulations as if rising to avoid some
invisible obstacle in the flight path. Between September and April
flights, numbering up to 20,000 birds, may be seen on the mainland
of Bahrain. Such large assemblies of birds seem to be mainly made
up of adult birds roaming far in search of huge shoals of fish.
Once a shoal is located some birds settle on the surface of the
water and dive for fish from there, whilst others plunge-dive
from the air. Since most of these dense flocks are seen in the
breeding season it is tempting to suppose that they originate
from the biggest colony in the region, South Sowad Island, in
the Hawar group.
Our observations indicate that birds start to leave the Hawar
colony from around 5 am, flying in a north-westerly direction,
and that by 7 am the number of individuals remaining has reduced
dramatically – indeed the colony is almost silent. The first birds
start to arrive back at the colony at around 10 am when they begin
to fly in, making ‘V’ formations of up to a hundred birds. Return
‘squadrons’ continue to arrive until sunset and our observation
of this particular colony suggest that large numbers continue
to arrive after dark. This would be consistent with fishing grounds
around and well to the north of Bahrain.
In the Hawar population Socotra Cormorants appear to begin to
congregate during September and in 1994, at least, numerous nests
had birds incubating 2 to 4 pale blue eggs on 6 and 7 of October,
when we visited. Interestingly, at this time there were very few
Herring Gulls attendant upon the colony. Later in the breeding
season predators feed voraciously on the young birds. There is
almost no information recorded relating to the breeding behaviour
of the Socotra Cormorant and it is certainly in need of further
study. Nests consist of a circular scrape or depression in the
ground, with raised edges, often decorated with stones. Throughout
the colony nests are arranged in groups of various sizes and may
almost be touching. Excrement appears to add concretion to the
nests as the season advances such that old nests are evident for
many seasons. As expected with the close proximity of nests, much
bickering takes place between neighbours and we have observed
that birds returning to the colony frequently make their way to
the wrong nest, eventually either realizing their mistake or being
chased off by the rightful owner. On the ground the birds are
relatively clumsy and often knock eggs out of the nest or even
break them.
At the start of the breeding season the adults are in peak condition
with velvet black head, neck, rump and underparts. The mantle,
scapulars and upper wing coverts exhibit a shiny dark bronze-green
colour. It has previously been recorded that breeding birds of
both sexes acquire white filoplumes on the head neck and rump.
We, however, have only observed such filoplumes behind the eyes
and even these were present in a relatively small percentage of
birds.
As the breeding season progresses the feathers become ‘tatty’
as a result of wear and coating with excrement. Breeding is asynchronous
and later in the season eggs, small and large chicks are present
in the colony. The incubation period is unknown but is probably
around 28 days. On hatching the young are rather ugly, naked pink
individuals with a disproportionately large head. After a few
days they become covered in a sparse white down on the back which
later covers most of the body but spares the face and underside
of the neck. At some stage, as they grow bigger, the parent birds
leave them in creches guarded by a few adult birds. They still,
however, remain vulnerable to predation by the large contingent
of Herring Gulls which take up residence on the edge of the colony,
using any disturbance as an opportunity to take even large chicks.
As time passes the colony becomes strewn with the bodies of chicks
of all ages. Marauding Herring Gulls will usually take large chicks
to the edge of the colony where they kill them by pecking a hole
in the chest cavity and leaving the rest of the carcass uneaten,
such is the abundance of potential prey.
Time to fledgling is also unknown but is probably about two months.
By late January the colony appears to be considerably smaller,
because most of the adults are away fishing, leaving a mobile
mass of nearly fledged young to form large groups around the breeding
area. Many dead and dying birds litter this section of the island
at this time. Since there is no evidence of injury from Herring
Gulls to many of the carcasses it seems likely that this is either
the result of parasitic infestation or starvation.
Chicks are fed by partial regurgitation. As adult birds land after
fishing trips they are chased around for several minutes by a
group of hungry youngsters, finally giving up food as the young
bird puts its head into the parents bill. Small chicks have also
been noted to seek food from larger chicks in a similar manner.
As the young birds mature grey-brown feathers with pale edges
replace the down but the breast and belly remain white for some
time. Immature birds exhibit a dark brown head and neck with a
paler throat and chin. The feathers of the mantle, scapulars and
upper wing coverts are dark grey with a brown-black spot at the
tip and a narrow white margin. The flight feathers are a matte
grey-black. Adult plumage is probably attained by the third year.
Ticks are said to be a major problem in some colonies and observers
who have strayed too close complain of a bite which causes intense
itching for days afterwards. In some cases a virus is transmitted,
which causes fever and severe flu-like symptoms. Fortunately we
have not experienced this inconvenience on the Hawar colony –
yet!
An annual excursion has taken place for many years to the Hawar
colony from the villages of Askar, Jau, and Dur. On such occasions
the young men of these villages arrive in motorboats to collect
eggs from the nests of the Socotra Cormorants. It usually occurs
in early October at the start of the breeding season. Large cool
boxes are filled these with the pale blue eggs. It is said that
the old men of the village believe that if they do not eat cormorant
eggs at least once a year they will become ill.
It seems unlikely that this practice causes any great threat to
this breeding colony as the timing coincides with the beginning
of the breeding season and thus the birds have time to lay a second
clutch of eggs. Some fishermen eat the meat of the cormorant during
the breeding season having caught them at sea. Birds caught outside
of this period are said to be scrawny and louse-ridden and are
therefore not taken. Presumably eating cormorant flesh must be
an acquired taste as the meat is said to taste strongly of fish.
Human activity in the Hawar islands is on the increase with more
visits to the main island but access to the main breeding island
is still controlled. There is a very strong case to be made for
continuing to protect this important breeding colony from human
disturbance. Whereas the early season egg-collecting is a traditional
pursuit calculated to sustain the breeding colony, visits in the
middle of the season will result in increased predation by the
large numbers of gulls ever present at the colony and will be
likely to severely impact upon the population. The Socotra Cormorants
is also vulnerable to the effects of oil spillages and is probably
the most commonly found oiled dead bird around the Bahrain coastline.
The Hawar Socotra Cormorant colony is just one of the treasures
of these stark and desolate but beautiful islands. With the added
attraction of breeding Sooty Falcons, ospreys, wintering Greater
Flamingoes and large numbers of dugong in the shallow waters just
to the north, it must surely be an area worthy of international
recognition and protection.