Gannets risk life and limb just to eat
Friday 9 Mar 2012 3:38 p.m.
By Josh Heslop
A study into the way gannets hunt for food has revealed how dangerous their dive-bombing antics can be.
Underwater footage shows the birds have to compete with sharks, dolphins and even other gannets to get a good catch.
And on top of that, collisions can snap their necks.
Gannets are amongst the most agile of seabirds, designed to plunge repeatedly for food with remarkable precision.
But a Massey University study has also found the drive for a good meal can come with disastrous consequences.
"They enter the water at high speeds," says Gabriel Machovsky Capuska. "They also have lots of predators in the same place. They have neck injuries."
Underwater footage of the cape gannet, taken off the coast of South Africa, shows how dangerous dive-bombing can be. The birds plunge into the sea, which is often teeming with other predators chasing the same catch.
Sometimes they even have to compete with each other.
"It's sometimes going to be easier to steal the food and they're going to save energy," says Mr Capuska, "however what we find is that there is a high possibility that stealing food, they can get injuries through that."
This free-for-all environment can lead to some serious injuries, as Mr Capsuka is finding out in his extensive study of the Australasian gannet.
Post-mortems on two carcasses collected from the Hauraki Gulf revealed the birds died from collision injuries, and the video footage backs up how easily it can happen.
"We discovered an approximation of one to two collisions every 1000 birds, and that depends on the food available, for sure."
Mr Capuska says fish stocks are healthy in New Zealand, but conditions are seasonal.
He will compete his thesis this December and hopes it will also shed light on human neck injuries.
Just be glad we don't have to go through what gannets do just to have fish for dinner.