The albatrosses

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Seabirds a case study
The albatrosses
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Albatrosses (family Diomedeidae) are large
seabirds allied to the procellariids in the order
Procellariiformes (the tubenoses).
They range widely in the Southern Ocean and the
North Pacific. They are absent from the North
Atlantic, although fossil remains show they once
occurred there too.
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Albatrosses are amongst the largest of flying
birds, and the great albatrosses (genus Diomedea)
have the largest wingspans of any extant birds.
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Most breeding birds share responsibility for
incubation of their eggs and change over at the
nest regularly to allow each partner to feed.
When the young hatch, the parents travel back and
forth to their nest many times a day with food.
Albatrosses, however, are completely different -
they spend many days at feeding at sea, often
thousands of miles away from the nest, before
returning to their mate or chick.
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The digestive system of albatrosses has an upper
stomach, or proventriculus, into which all of the
food passes for initial digestion. Squid, fish,
krill and other items on the albatross menu are
broken down into a mixture of water, fats,
proteins and everything else. The lower,
muscular section of the stomach (gizzard) acts as
teeth grinding food material into a soft pulp
and blocking the passage of bones and other
objects that might injure the internal tissues
The oil layer floats to the top, while
water-soluble proteins and other compounds settle
to the bottom. The lower water layer is allowed
out of the upper stomach into the lower gut that
then continues to digest and absorb it in the
normal way, making room for more food. When the
bird is finally full, it returns to its island
home.
The oil is a ready source of energy and can
easily be regurgitated as food for the youngs.
This means that the chick can be fed, while the
adult has enough energy for itself, not needing
to feed again for several days.
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Current thinking divides the albatrosses into
four genera. The number of species is a matter of
some debate. The IUCN and BirdLife International
among others recognise the interim taxonomy of 21
extant species, other authorities retain the more
traditional 14 species, and one recent paper
proposed a reduction to 13 - Great albatrosses
(Diomedea) wandering albatross D. exulans
antipodean albatross D. exulans antipodensis
amsterdam albatross D.exulans amsterdamensis
tristan albatross D. exulans dabbenena northern
royal albatross D. epomorpha sanfordi southern
royal albatross D. epomophora - North Pacific
albatrosses (Phoebastria) waved albatross P.
irrorata short-tailed albatross P. albatrus
black-footed albatross P. nigripes laysan
albatross P. immutabilis
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- Mollymawks (Thalassarche) black-browed
albatross T. melanophris campbell albatross T.
melanophris impavida shy albatross T.
cauta chatham albatross T. cauta eremita salvin's
albatross T. cauta salvini grey-headed albatross
T. chrysostoma atlantic yellow-nosed albatross T.
chlororhynchos indian yellow-nosed albatross T.
chlororhynchos carteri buller's albatross T.
bulleri - Sooty albatrosses (Phoebetria)
dark-mantled sooty albatross P.
fusca light-mantled sooty albatross P. palpebrata
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Nineteen of the worlds 21 albatross species are
seriously threatened by longlining. This is the
highest proportion of species under threat of
extinction of any bird family. Why are they
so vulnerable? Albatrosses are long-lived
birds - some live up to 60 years. They only breed
once they are fully mature, which can take
several years. And they only produce one chick at
a time. Some species only breed every two years.
Adults are being killed on longline fishing hooks
in such vast numbers that they cant breed fast
enough to keep up.
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Most at risk
(IUCN data source) amsterdam albatross
Critically Endangered number of breeding pairs
remaining 17 chatham albatross Critically
Endangered number of breeding pairs remaining
4000 tristan albatross Endangered number of
breeding pairs remaining 801 black-browed
albatross (albatro dal sopracciglio nero)
Endangered number of breeding pairs remaining
787959 Erratico dagli oceani del sud alleuropa
occidentale. Recenti avvistamenti regolari in
Scozia sono attribuibili ad un individuo singolo,
soprannominato Albert, che estiva in colonie di
sule (Hermaness, Unst, Is. Shetland) wandering
albatross Vulnerable number of breeding pairs
remaining 9188
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Albatrosses have large, long, hooked beaks, each
made up of 12 distinct plates. Made of keratin,
they are dark in young birds, but gain colouring
as the birds mature, attaining bright yellow and
orange colours in some species. The beak is
strong and sharp-edged, with a stout hook at the
end of the upper mandible, ideal for grabbing
hold of slippery fish and squid.
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What do seabirds drink ?
Seabirds have developed special salt-secreting
glands located above the eye, over the bony
orbit, and they secrete collected salt into the
nasal passages just anterior to the eye. These
salt glands have a microstructure similar to the
kidney and use a system of countercurrent blood
flow to remove and concentrate salt ions from
bloodstream.
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In black-footed albatrosses, each nostril is
divided into two openings, one for excess salt
and the other for incoming air They have large
olfactory lobes, indicating that they have a
well-developed sense of smell this may help them
to detect distant food sources. It may also help
them to recognise each other at the breeding
colony albatrosses have a distinct musty odour
that comes from their strong-smelling stomach
oils.
When above water, albatrosses breath through
their nostrils and when diving, a valve stops
water passing through into their airways
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Quite different physical principles underlie the
soaring flight of the albatrosses. There are no
thermals over large bodies of water, only
horizontal gusts of wind. The air masses that
these gusts drive before them are slowed by
friction at the water surface, and their speed is
consequently slower than in higher altitudes.
These seabirds have developed a type of soaring
and gliding that does not depend upon the
presence of either thermal or obstruction
currents. Seabirds use the differential wind
velocities that occur over the sea for their
soaring flight. Albatrosses, for example, take
off against the wind, rising without beating
their wings, until they lose momentum in the
faster-moving layers of air farther from the
water surface, at the height of about 35 to 65
feet. The birds then turn in a curve and shoot
back to the water surface in an oblique gliding
path, gaining so much speed that after turning
back again they can once more climb against the
wind. In this way albatrosses cab soar for hours
and days at a time without ever beating their
wings.
It is this semmingly endless form of flying that
allows the albatross to survive, since
albatrosses cannot fly in the absence of wind.
This is a significant factor in their latitudinal
distribution.
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Albatrosses have declined in the past due to
harvesting for feathers, but today the
albatrosses are threatened by introduced species
such as rats and feral cats that attack eggs,
chicks and nesting adults by pollution by a
serious decline in fish stocks in many regions
largely due to overfishing and by long-line
fishing.
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Longline fishing boats unwind long lines off the
back of the boat. Each line has hundreds of hooks
with squid bait. There are several different
types of longlines. They have buoys at the top
and some are weighted so they sink.
Before the lines go off the boat the fishers dump
fish guts off the boat to attract fish, but this
also attracts albatross.
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Thousands of hooks are attached to lines. Some
lines can be an incredible 80 miles long and
carry up to 10000 hooks. These are towed at depth
behind fishing vessels.   Hundreds of fishing
boats set millions of fishing hooks every year
and thousands of albatross get caught and die.
Some albatross species have decreased by 90
since the 1940s, others have decreased by 40-50
because so many albatrosses drown on fishing
hooks. It is most likely that some albatross
species will become extinct before 2012 if this
killing does not stop.
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The albatrosses are attracted to the fishing
boats because they know they can get a free feed.
They try to take the squid from the hooks to eat.
Sometimes they are successful and eat the squid.
But a lot of the time the hook gets caught in
their beak and they are pulled under water and
drown.
It is estimated that around the world about
300000 seabirds (including albatross and petrels)
are dying on longline hooks every year.
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There are a number of things that fishers can do
to significantly reduce the number of seabirds
being caught on longlines
Put the longlines out at night birds usually
feed during the day
Do not have too many bright lights on at night
when they are fishing
Don't fish either side of a full moon (about 5
days), because the albatrosses can see the boat
and bait.
Use weighted lines to help the lines sink faster
Use streamers to scare the birds away. Light
streamers that fly from the back of the boat over
the area where the longlines are being dropped
work well- they scare birds away.
Dont throw fish guts into the water before the
longlines go into the water, wait until the lines
are down.
Put Ministry of Fisheries observers on the boats
Forbid fishing at times and in places where
seabirds gather to feed.
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Ingestion of plastic flotsam is another problem
faced by many seabirds.The amount of plastic in
the seas has increased dramatically since the
first record in the 1960s, coming from waste
discarded by ships, offshore dumping, litter on
beaches and waste washed to sea by rivers. It
is impossible to digest and takes up space in the
stomach or gizzard that should be used for food,
or can cause an obstruction that starves the bird
directly. This plastic is sometimes
regurgitated and fed to chicks. While not the
direct cause of death, this plastic causes
physiological stress and causes the chick to feel
full during feedings, reducing its food intake
and the chances of survival.
Movie (438) Albatross the end of the line
(BirdLife International RSPB - 2006)