Nestled on the western coast of South Africa
lies an extraordinary cove;
Host to an abundance of marine and bird life,
Catering for scores of visitors,
as well as many permanent residents.
Providing ample food;
And spurring a life cycle that reaches well beyond Africa.
This is the Blue Lagoon.
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The word "lagoon"
roughly translates to "a lake of salt water".
Langebaan's is one of the few in South Africa
that actually fits this description.
Unlike most other termed "lagoons", it's fully saline.
And is fed by the Atlantic ocean.
In a small area of 18.5 square miles,
it holds a wealth of habitats within its borders.
Located in the middle of a semi-desert,
the lagoon breathes life into an otherwise harsh ecosystem.
Although small, it's a particularly productive place,
offering plenty for all creatures on its shores.
As a result each year thousands of migrant waders
arrive from the Northern Hemisphere
to feed and find shelter.
And the lagoon's resources are stretched thin.
It's late winter
and the visiting hordes are yet to arrive.
The tide is reaching its lowest
and alien markings freckle the sand flats.
These are remnants of a particular resident's
strange habits.
The rising tide
reveals the culprit of these bizarre markings:
Greater flamingos.
These birds of absurd proportions
stalk the calm waters.
Vivid in color and peculiar in shape -
they comb the lagoon for sustenance.
Their fluffy pink bodies sit suspended above the tide,
Balanced precariously on two long, thin legs.
And with these, they kick up a storm on the lagoon floor.
Moving in circles
while rhythmically stamping their feet,
they uncover any crustaceous prey
that might be hidden in the sand -
Leaving circular imprints in the mud,
seen when the tide goes out.
These patterns are of great significance for the lagoon.
This feeding strategy
does more than stir up food for the flamingos;
it also churns the sediment of the lagoon,
preventing stagnation.
Thanks to these birds, the lagoon floor is kept healthy,
helping other creatures to feed.
The combined effect of hundreds of stamping feet
stirs clouds of mud from the lagoon.
The true impact can be observed from the air.
The flamingos are the gardeners of the lagoon,
sifting through the compost and promoting growth.
While they demand high volumes of food from the lagoon,
they also return vast quantities back to the water
via their feces.
The crustaceans in their diet color them rosy pink
due to the carotenoid pigments.
The bright colors are best seen however,
when they take to the air.
Here, they can feed with abundance
thanks to the high concentration of tiny marine invertebrates.
Flamingos use a highly specialized method of feeding.
Their diet of small crustaceans including shrimp and copepods
are abundant in the sand flats;
But catching them needs particular equipment
in the form of long legs and an unusual beak.
The flamingo is the only bird that feeds
with its beak pointing backwards and upside down.
This method allows it to skim through very shallow waters.
Pumping its tongue like a piston,
the flamingo flushes water and sediment through its beak -
filtering out food
with hair-like structures called lamellae.
This is a very similar foraging system to that of baleen whales.
But some birds find it easier to let others do the work for them.
The opportunistic Hartlaub's gull
follows behind the pink bird,
Picking off the leftover dregs.
Little egrets prefer fishing for themselves.
Even if this means a bit of dancing around.
The Caspian tern however,
will only expend its energy
if it knows chances are good.
The Langebaan lagoon's crystal clear water
makes an ideal feeding site for this skydiver.
Feeding visually is a popular tactic among birds.
The Pied avocet is a local member of the community.
Combining visual and tactile strategies,
this bird has an unusual way of feeding.
The avocet uses its upturned bill
for scything side-to-side through the water -
picking up crustaceans and insects.
Langebaan lagoon allows these birds
to find food all year round.
As the winter months draw to a close
a late flurry of rains injects the area with a dose of energy.
The hillsides surrounding the lagoon burst into life.
Food multiplies exponentially.
And the locals make the most of this time.
As winter transforms into spring,
Langebaan lagoon welcomes visitors from afar.
In August almost 50,000 seasonal waders arrive.
Small flings of Whimbrels, sandpipers and plovers
descend on the lagoon's rich waters.
They have been traveling for the past 4 months
and have covered more than 6,000 miles.
But the lagoon is ample reward for their mammoth migration.
The health and future of the migrant waders
is dependent on this small cove.
Without it, several populations of birds
would have nowhere to replenish their reserves
after their long journey south.
This is their final stop on the African continent.
They will spend the next few months here,
eating everything they can to build their stamina.
Just as the flamingos and avocets
have their feeding strategies,
so too do the migrants.
The Grey plover depends entirely on his sight to catch food.
His short beak isn't very useful for probing,
so he must first locate his prey
and then commit to the stab.
He needs space to feed
and can become very territorial over his feeding grounds.
Others prefer a more tactile method.
Curlew sandpipers stab haphazardly into the shallows,
But their highly sensitive bills
will feel if any morsel is close.
The Whimbrel uses a similar strategy
but with one difference.
His bill is longer,
so he can continue foraging as the tide starts to rise.
Regardless of one's foraging method,
feeding can be a tricky practice.
Especially when the meal bites back.
The outskirts of the lagoon have sprung to life
with the arrival of spring.
The creatures are excited, relishing the new blossoms.
Playful fighting among the eland
and courting between the Bontebok
means life is good and thriving.
New flowers attract pollinators,
and the pollinators attract hungry birds.
Cattle egrets usually rely on the antelope
to disturb insects hidden in the grass.
But with the abundance of insects all around,
they now have a chance to be self-sufficient.
A few Sacred ibises join the egrets,
and the dexterous swifts
skillfully snatch their prey on the wing.
Nearby, a flock of kelp gulls makes a rare foray inland
to take advantage of the multitude of insects on offer.
But some inhabitants prefer a quieter life -
and make their home in the sandy surrounds
away from the frantic feeding in the fields.
The Namaqua rain frog
doesn't live in water.
Instead, he spends most of his time buried underground,
surfacing after the rains to feed on insects.
For one particular endemic local,
something other than insects keeps them here.
The fresh grass provides perfect material
for male Cape weavers to build nests -
Which is not the easiest task.
The male is at the mercy of the female.
She will select a mate based on the quality of his craft.
After building each nest the male performs for the female,
Trying to entice her into inspecting the nest.
Only the strongest of nests will be suitable
to raise a brood of chicks.
If the nest isn't up to scratch
the male will often demolish his creation and start over.
But if the female approves
of the male's construction abilities,
she'll allow him to mate with her
and she'll lay her eggs in the very same nest
that won her over.
It's a tiring process for Cape weaver males
and a definite level of skill is needed
in order to secure reproductive success.
Traffic in the lagoons
is ruled by the changing of the seasons.
And on a smaller scale,
the daily rhythms are governed by the tides.
Twice a day the water level of the lagoon drops
as the Atlantic pulls out to sea.
For some,
the shallows open up a huge foraging plain
rich with food.
But for others, things are a bit more complicated.
Goby fish thrive in intertidal pools;
these are above water at low tide
and submerged at high tide.
They enjoy shallow waters
and the scurrying food that comes with it.
But sometimes, they can overestimate their abilities.
As the water level drops,
their moisture-dependant skin becomes exposed.
They're at risk of drying out.
But they've evolved to deal with situations like this.
Their strong pectoral fins
allow them to push off into deeper waters -
escaping the drying sun.
They'll be able to continue enjoying the resources
provided by the lagoon.
As the tide continues to retreat,
it reveals a bounty of life on the sand
and mud flats.
A plethora of mollusks, crustaceans
and other invertebrates is on offer.
Both the migrant birds and the locals
depend on the Blue Lagoon
because of this ample tidal zone.
The birds gorge themselves.
The lagoon is a biological factory.
Its various microhabitats all work together
to ensure the smooth functioning and production
of the entire mechanism.
Delving into the lagoon's depths
reveals an array of weird and wonderful creatures.
The Sand slug glides along the bottom of the lagoon -
Leaving traces of his daily missions.
Although a seemingly harmless creature,
he can be a ruthless killer.
He glides over a crab,
attempting to swallow it whole with his muscular stomach.
But today, he's unlucky.
He also manages to ward off any curious individuals
by constantly secreting
lethal sulphuric acid through his tissues.
Another crafty creature lives alongside the bold Sand slug.
Thousands of small holes on the sandy bottom of the lagoon
hint at an unassuming animal beneath the substrate.
A subterranean engineer works tirelessly,
constantly filtering the sand.
This is the Sand prawn.
And although small, its effect on the environment is vast.
Without this species,
the lagoon would not be able to function as it does.
Its huge pincer makes digging a quick activity.
A fine net of hairs
covers its first pair of legs and mouthparts
to form a basket that holds and sifts the sediment,
separating out and eating the organically rich particles.
A shovel-tipped leg pats down the wall of the burrow,
keeping its structure in place.
Paddle-like limbs pump back and forth,
circulating water through the sand tunnel
while the tail wedges the animal in place.
The sand prawn has a flexible back
which allows it to turn around
and move freely in its restrictive home.
The small eyes of the prawn
are of little use to it in these burrows;
the two pairs of sensory antennae
provide much more valuable information.
Although some of the organic matter
is digested and absorbed by the Sand prawn,
much of it is passed out and neatly packed up
in their sausage-like feces.
This allows the bacteria, fish and wading birds
access to the otherwise buried nutrients.
And there's no shortage of these nutrients.
In a 1 mile stretch of lagoon,
the resident Sand prawns
can produce up to 200 tons of feces a year.
This is a valuable addition to the surface sediments
and can actually affect the composition
of the entire lagoon bottom.
The Sand prawn plays an important role
in the ecology of coastal zones.
Without this species,
the lagoon would not be able to function as it does.
And the fish and birds surrounding the cove
would have nothing to eat.
But the provider can quickly become the prey.
This prawn is busy digging a new home for itself.
But building these tunnels renders it vulnerable,
so it needs to work fast.
Many predators lurk nearby,
waiting for an opportunity to strike
A batch of eggs is a bonus for a hungry hunter.
Towards the southern part of the lagoon away from the ocean,
the sand gives way to a different substrate -
Mud.
Here a similar species resides -
the Mud prawn.
Despite a differently shaped tunnel,
these creatures play a similar role as the Sand prawn.
But they lack the massive pincers
of their sand-dwelling counterparts
so digging requires more effort.
This individual has chosen the path of least resistance.
He's investigating holes that have already been dug out
by other prawns.
Most of them prove unsuitable.
After much inspection he finds one with potential.
But it already has an inhabitant.
The house hunter will either have to continue his search
or build his own.
The prawns and the nutrient-rich environment they create
allow the migrant waders to fatten up
before their long journey north.
So these two small crustaceans exert an influence
that reaches well beyond the shores of the Langebaan lagoon
to continents far and wide.
Both species of prawn and the flamingos
work and modify the sediments
through their own unique feeding methods.
And without them, the Langebaan lagoon would not be able to host
its vast array of life.
Throughout Africa,
Greater flamingos feed side by side
with their closely related cousins,
the much smaller and darker-billed, Lesser flamingos.
The large, paler Greater flamingos
have a much coarser filter system than the Lessers,
so they target different prey.
So many beaks in the same waters can make tempers flare.
It's the afternoon, and the tide is changing.
The water pushes in from the ocean.
As the lagoon draws higher over the sand flats
the short-legged birds retreat.
The taller flamingos, on the other hand,
don't face this problem.
Their longer-than-average legs
allow them to forage in the lagoon
with little hindrance from the rising tide.
They have much more access to the lagoon than the small waders
and can forage for longer periods.
There is an alternative right next to the sand flats
that provides a place for the short-legged birds
during the high tide -
The salt marshes.
These vast stretches of vegetation
surrounding the Langebaan lagoon
are the largest salt marshes in South Africa.
Without them,
the migrants would not be able to visit the cove
during high tide.
They depend on this habitat twice a day,
as a refuge from the current
and for more food.
This place teems with life
in the form of fish and crustaceans,
Creating a buffet for the birds.
The saline-adapted vegetation
is able to extract nutrients directly from the mud.
It also acts as a natural sieve,
like a giant sponge filtering the sediment
and preventing silt from going into the lagoon.
The marshes provide a sanctuary for the waders during high tide.
The edge of the salt marsh
hides an endangered and endemic creature
that numbers fewer than 2000.
The Black harrier.
Every spring they gather
to raise a new generation of raptors.
There's been good rain this year
and the dune vegetation
is displaying its kaleidoscope of colors.
The landscape is fresh and lush
and is exactly what they require.
Black harriers build their nests on the ground,
which renders the young vulnerable to predators.
This female has successfully hatched two chicks.
But growing them to a fledging age
is an entirely new challenge.
The mother doesn't do any hunting at this stage,
and is totally dependent on her mate for food.
She waits anxiously for the male
to bring food for herself and for the chicks.
He has been gone for a while and she calls out for him.
Finally, her mate returns.
Food at last...
a brief landing delivers the prey at her feet.
But he doesn't stay for long and resumes hunting.
The female is meticulous
about not leaving any scraps lying around the nest.
These could attract an array of predators.
But it's already too late.
The smell of the prey has enticed a Pied crow,
which feeds on small mammals, carrion and baby birds.
She huddles over her babies,
hiding them from the leering predator.
Eventually the crow leaves,
restoring peace to the anxious mother.
These chicks will live another day
in the shelter of the lagoon and their mother.
As summer draws to a close, the migrant waders will soon depart.
They've had their fill of food from the lagoon
and are now strong enough to commence their journey north.
There'll be less competition for food
so the resident birds will have enough
to raise offspring of their own.
They'll soon begin breeding
and new life will continue to flourish in the lagoon.
As another cycle of the seasons starts anew,
life on the water goes on as ever.
The Langebaan lagoon has six months to replenish its stocks
before the throngs of visitors return.
This small retreat on a semi-desert coastline
is an oasis of global importance.
It provides creatures near and far
with the food they need to survive.
They can continue their legacies in the far corners of the world,
But they'll always return
to the bountiful,
Blue Lagoon.
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