BP has begun its long awaited "top kill" operation to try to stem the flow of oil from beneath the Gulf of Mexico.

There are no guarantees it will be successful - even President Obama says so.

BP's chief executive says so far the operation is progressing as planned but "top kill" can't come too soon for the people of Louisiana, who are concerned about their livelihoods and their wildlife.

The online pictures BP is providing are amazing. They are never-before seen shots of an underwater operation never-before tried at this depth.

The sci-fi equipment is pumping heavy mud straight into the gushing oil riser.

Top kill works like this: Vessels on the surface of the sea carry pipes that have been lowered deep into the ocean. The pipes shoot a heavy mixture into the broken riser, hopefully killing off the high pressure jet of oil spurting out of the seabed. Cement will be used to seal it off.

If the mud from the "top kill" doesn't do the trick, BP will have to think again.

Among its options is a so-called "junk shot" to help plug the hole - the junk could include old tyres, golf balls, tennis balls and even bits of rope - again topped off by tonnes of cement.

As BP began top kill, Louisiana's governor, Bobby Jindal, led a delegation back into the wetland marshes to see if the oil was as bad as it was the last time he went out at the weekend.

The governor said it was.

"Heavy thick oil is still there … an area that should have been teaming with life was literally still - you could see the discolouration of the canes. This, again, is one of the most important nurseries for the Gulf."

And wildlife is what the battle to stop the oil leak is all about.

Louisiana's famous Pelican Island is home to hundreds of Pelicans – the state bird. Recently declared safe from extinction, it's now once again in danger.

We filmed a Pelican that can be classed as one of the lucky ones. Sticky with oil, the bird's now been cleaned up at an animal rescue centre in Fort Jackson.

Rebecca Dunne from Tristate Rescue and Research told us:

"At this point daily we're seeing four to six birds … we've actually been here for a month already and we have very few birds compared to what we normally see."

The hope is BP will get lucky shutting down oil from the Deepwater Horizon well to keep this disaster from growing and continuing to put the Gulf Coast in peril.