Hear about why seagulls are proving to be a pest, not only for people at the beach, but for the environment as well.


MIKE SEXTON: Australia has only two endemic species of seagulls, the Pacific gull and the silver gull.

But what they lack in variety, they more than make up for in noise.

And the din they make grows louder every year, because gulls are the baby boomers of the bird world.

JEREMY ROBERTSON, FLINDERS UNIVERSITY: They've absolutely exploded.

Since the Second World War, the numbers have gone up exponentially.

They're just increasing fantastically.

MIKE SEXTON: Biologist Jeremy Robertson from Flinders University has been studying seabirds at Port Adelaide for almost a decade, against the industrial backdrop are several islands that are home to major bird colonies.

And although it's impossible to quantify how many, Dr Robertson has seen the area increasingly dominated by silver gulls.

Unlike parts of nature where the spread of human activity has endangered species, the silver gulls thrive because they live off the excesses of our lifestyle.

JEREMY ROBERTSON: They're opportunists and they've, they're taking advantage of human activities - rubbish dumps, for example, fishing discards, aquaculture, that kind of thing.

And just the Australian outdoor life, if you like. Barbeques and things mean there's a lot of excess food around. And gulls really don't, in many cases, live in the wild anymore. They live around people and that's why they're doing well.

MIKE SEXTON: A short flight from Port Adelaide is one of the city's largest dumps and a perfect example of why silver gulls are often referred to as 'rats with wings'.

This scene is repeated around the world, making the spread of seagulls not only a problem for Australian cities and towns, but a global phenomenon.

Twenty years ago, Ian Temby authored a report for a Victorian Government inquiry into waste management that recommended ways of controlling seagull access to tips.

Now he believes the message is even more urgent.

IAN TEMBY: Now we have a figure for the costs to the community of having so many gulls around.

And that, I hope, will provide the spur to get groups of interested people - and that's businesses, airports, municipalities that are affected by these gulls - to get together and lobby for change to the way we handle rubbish.

MIKE SEXTON: Back at Port Adelaide, Jeremy Robertson believes silver gulls have already driven away some terns and are threatening a breeding colony of cormorants.

JEREMY ROBERTSON: The silver gulls, which you can see hanging in amongst the cormorants, will move in and take chicks whenever the nest's left, even for only a few seconds.

So there's a very high mortality of chicks. We've seen 100 chicks taken in a few minutes. It's just extraordinary how quickly they go.

MIKE SEXTON: The best way to lower their number is to cut off the gulls' free lunch.

But Dr Robertson warns against any drastic action, fearing that we've tipped the balance of nature so far one way that anything other than a gradual reduction in food for gulls will see them destroy other species.

JEREMY ROBERTSON: Let's say we effectively close down dumps so gulls couldn't get at them they would have to find alternative food sources and the most likely thing is they'd turn on other birds and things and you could have a real environmental disaster.