THEY’RE becoming the new terror of the skies – and this week Dúlra witnessed it at first hand.

He was walking through the city centre when suddenly, a seagull pounced from the air on to a pigeon which had been walking on the road.

The screeching was so loud that shoppers stopped to take in the commotion. The seagull sank its giant beak into the pigeon's back and started shaking it like a ragdoll, as you can hopefully see in Dúlra's mobile phone pic.

The pigeon struggled for its life and was saved by an oncoming car which forced the seagull back into the air for a moment. The badly injured pigeon took the opportunity to run under the blue car in the picture.

The seagull returned to finish off its prey, but it couldn't fit under the car. So it forced its head under and squawked terrifyingly, trying to scare the pigeon out. But the injured bird stayed put and the seagull had to take off into the sky, its stomach empty.

Dúlra and all the other shoppers then continued about their business, trying to process the brutal snapshot of the natural world that had shattered our civilised afternoon.

And it struck Dúlra like never before: nature is changing before our eyes.

Where once birds of prey ruled our skies, other species have filled that gap. Magpies kill more garden birds than sparrowhawks, and seagulls kill more pigeons than peregrine falcons.

We can’t paint all gulls with the one brush – just like we can’t paint pigeons with the one brush. Dúlra remembers meeting an excited birdwatcher at Belfast Lough whose day – maybe year – had been made after he focused his telescope on a rare Icelandic gull. And again, during a trip to Tory Island, the experts weren’t raving like Dúlra about the hundreds of puffins, but on what looked like a single, boring pigeon on the opposite rockface. It was a rare, wild rock dove.

The city centre pirate was a herring gull, faoileán scadán (mackerel gull) in Irish. Go back a few decades and it was only to be found on our coasts. But it realised that inner city office blocks were much safer bets to raise families and the population there took off. In the 1970s, its population increased on average by 13 per cent every year, and its survival rate was 93 per cent – incredibly high for any bird. By the end of that decade they were often considered a problem, even divebombing the occasional shopper.

They are still protected under the law, but getting a licence to limit herring gulls is as easy as getting a fishing licence.

They used to be poisoned, but today the most popular culling method is more ingenious – removing their eggs from their nest and replacing them with plastic ones. The mothers actually incubate the plastic eggs for twice as long as normal – two whole months – during which time they are as quiet as mice.

And by the time they realise that the eggs haven’t hatched, breeding season is over.

Another method is to hire a gull-killing bird of prey – one of the traditional predators that we no longer have.