Tiger shark v baby albatross

THE SHOOT: Tiger sharks predating albatross chicks
LOCATION: French Frigate Shoals
CREW: 1x Producer, 1x Dive Supervisor, 2 x Cameramen, 2 x Safety Divers
SETUP: Liveaboard base, Zodiac for dive support

It takes us two days' solid steaming from Honolulu to get to French Frigate Shoals, a collection of sandy specks and spits in the remote North-west Hawaiian Islands.
Uninhabited, they are home to hundreds of thousands of ground-nesting birds, as well as green turtles and endangered species such as the laysan albatross and Hawaiian monk seal.
It is illegal even to enter the surrounding waters without a permit, and the area is so protected that few film crews are ever allowed access. It's a big operation, and Mark Brownlow, Producer of the Endless Blue episode of South Pacific, is directing and heading up the shoot. I'm here as Dive Supervisor and an extra pair of hands.
We're here for the annual albatross fledging, and we're not the only ones. Each year, just as the birds are ready to take their maiden flights, the tiger sharks arrive. No one knows exactly how they time their arrival, but research shows that some, like us, have travelled the 500 miles from the main Hawaiian Islands to attend this event.
Once anchored, we take one of the RIBs and head over to recce the filming location. East Island is just a narrow, low-lying mound of sand a few hundred metres long. Unfortunately for the chicks, this means that their first flight must be over water. Some will touch down with a splash, giving the tiger sharks their opportunity.
The moment the shark strikes the birds is the key to the sequence, and we want to get this from both above and below the water. On topside camera is John Aitchison, a renowned long-lens man, who will be able to follow the shark action from above with amazing close-up shots.
However, to get the right angle and vantage point he needs a platform. The islands are strictly protected, and with the vast numbers of ground-nesting birds, building even a temporary structure on land is out. We plan to build in the lagoon itself.
Matthew D'Avella and I hop into the water and begin construction while the topside crew hand us materials, and keep vigilant for tiger sharks. Under water the vis is less good than I'd hoped, but with two boats anchored right above us, and all the clanging and banging, it feels pretty safe.
The sandy bottom is quite flat, and it's not too hard to get the structure level. The scaffold goes up pretty quickly, and in only 12m of water we break the surface in less than an hour. We put a platform at 15m to give enough wave clearance to keep John and his equipment dry, then add a guard-rail - mission accomplished.
I had trialled the structure in Honolulu, but it was good to see it all come together. Out here, there's no nipping to B&Q if a bit's missing.

FIRST DAY OF FILMING and we're all up before dawn, necking coffee and fuelling up. We install John on his 3 x 2m platform, his base for most of the next fortnight.
There's little more space on the dive-boat. With the underwater camera, dive equipment, four divers and driver, it's fairly cosy. Veteran shark-diver and underwater photographer Doug Perrine is Richard's main safety diver, and Hawaii local Matthew D'Avella will be surface standby.
I will be Dive Supervisor and operate the Making Of camera - getting the guys' reactions and thoughts as the shoot progresses.
It's impossible to predict where an attack will occur, so the only way to get the shots is to watch the birds. The albatross "chicks" are really quite large at more than 50cm tall, with a wingspan of approaching 2m - a decent meal for any shark.
The most advanced pick their way down the beach to the water's edge and stand, looking blankly out to sea. The compulsion to fly is there, but they don't seem sure what to do about it.
As we wait in the boat we catch the day's first tiger sighting. It's a large shark, a bulky shadow cruising slowly between us and the shore.
The chicks continue testing their wings, oblivious of the threat lurking metres away.
Finally, as the breeze blows stronger, the first chick strikes out. Like a small miracle, it flaps across the bay 5m above the water's surface. But then it starts to lose height.
We watch, willing it to lift back up and vanish towards the horizon, but as it dips lower and lower, it's apparent what's going to happen.
It's time to move if we're to be there for a shark hit. We crank the engine and speed to meet the bird's trajectory. Easing to a halt some distance away so as not to disturb bird or shark, Richard and Doug will have to swim the last 25m under water.
It's a race. To minimise drag, I have arranged slimline sports harnesses and low-volume small cylinders, but I don't envy the guys their underwater swim.
Once in position, Doug will watch Richard's back at all times, and carries a "shark billy"
to prod anything that come too close. All the advice is that in this situation the sharks are so cued-in on the birds that they will take no interest in divers.

THE BIRD TOUCHES DOWN on the water, and Richard and Doug stop within sight and wait. John Aitchison and Mark are covering the action from the platform.
The chick bobs on the surface without a care in the world, a sitting duck. We see a shark enter the lagoon, but it skirts the edge of the reef and disappears again. Time ticks on, and the bird takes in the view. Bubbles continue to rise, but nothing else happens. It's the luckiest bird alive.
A full 10 minutes later, it takes the initiative. Its eye gleaming with determination; it flaps again, scrabbles its feet along the water's surface, takes to the air and is gone.
Richard and Doug surface shortly after. They haven't so much as seen a shark, though they've been on high alert. We pick them up, and they prepare for the next opportunity.
The next bird that flies touches the water only for a moment before taking off again. Several make it to a life on the wing on their first attempt. Then another bird flies, gets quite far but, just as we think it's going to make it, starts to lose height.
We're on the case, cranking the engine to get there in time. We slow to a halt, spray flying everywhere, but as I'm filming Doug and Richard roll in, and I hear the others shouting. A big shark is heading straight for the bird, barely 20m away.
I move up just in time to see the pale head emerge above the surface. Its jaws open wide, then crunch down on the albatross.
Its wings splay, and in moments it's gone. It's the first strike any of us have seen, a brutal display of nature at work. Richard and Doug clamber back into the boat, breathing hard from the effort and adrenalin. We can't believe how close we were, but the shark has won the race this time.
As the morning goes on there are a few more touch-downs, and even a couple of shark strikes. This sets the pattern for the next few days, as we repeatedly race the sharks to get to the birds, but each time either the shark gets there first or, once the guys are in position, there's no hit.
With the vis poorer than expected, the guys are having to wait closer to the bird than we had thought. There's no way round it if they are to be close enough to film, but the proximity might be putting our tiger sharks off their lunch.
After a few days the visibility drops to barely 5ft, and it's decided that it's too dangerous to go in.
Meanwhile, John and Mark are cleaning up on the topside platform. Even though it all happens within sight of the beach, the fledglings remain ignorant of the danger of a watery landing. John gets shot after shot, as enormous sharks erupt from the water to take the birds. Wings splay, jaws crunch and the water foams.

THE ODDS SEEM STACKED in their favour, but sometimes the sharks miss, their approach generating a bow-wave that washes the bird forwards, away from the gnashing jaws.
Other times, an amazing battle of shark v bird ensues. One albatross literally hops and dances on the nose of the shark in an attempt to get away.
One of the most fascinating moments happens when a tiger shark very nearly gets a bird. It pushes it around on the surface, but never quite manages to grab it.
Then, in a miracle moment, the chick escapes. The shark goes ballistic, thrashing and turning in circles in a high-energy search for its missing prize. The water foams and churns white; it's a sobering demonstration of what an angry shark can do.
Each time we witness the event there is the mixed emotion of rooting for the bird, but also the shark. As if to underline the connection between this annual food bonanza and the next generation of tiger sharks, research has shown that many of those that come here are pregnant females.
After a few frustrating days the visibility clears up, and the divers can get back in the water.
Time's short, and we still don't have the underwater attack to complement the topside footage. Doug is convinced that scuba bubbles are deterring the sharks, and this time the two will wait by the bird on snorkel.
It's not ideal, as a surface position is more open to attack, but the sharks have shown little interest in the divers for more than a week now.
Again the bird flies, we drive to meet it, and the guys begin their hard swim. We all watch and wait as the bird bobs on the water, unconcerned.
Suddenly, there's a shark in the area. We glimpse it as it heads toward the location of the bird, and then it's gone.
The next thing we see is the hit. This shark is efficient. She takes the bird in one gulp and is off.
We head straight over to pick up the divers. Richard and Doug are buzzing with energy; as they surface they can't believe they were so close to such an awe-inspiring event.

But did they get the shot? To find out, watch the South Pacific series on BBC2, which started on 10 May. Endless Blue, including the Making Of shark/ albatross segment, seen on 24 May.