You have probably experienced it at some stage. The sudden whoosh above your head causing you to duck in fright. Looking up, you see a flash of black and white as the magpie banks around to have another go at you.

It's a classic Australian phenomenon, and now magpie victims can report their attack on a website called magpiealert.com.

The website shows a map of all reported magpie swoopings in Australia, including those which cause injury.

The brains behind the website is Sydney IT manager Jon Clark. He says that by mapping magpie attacks, it can "help others to avoid the dangerous birds".

How did the idea of a website come about?

"It all started a couple of years ago in 2013 after getting swooped whilst out on my bike," Mr Clark says on the website. "I got home and started searching the internet for information on attack prevention and perhaps somewhere I could register the attack.

"I found a number of websites ... but nothing in my area and nothing across Australia."

At the time of publication, the website showed 2945 attacks and 397 injuries this year.

The eastern suburbs and inner west appear to be magpie hotspots, while the north shore is either magpie-free or the attacks go unreported.

Research has shown that magpies remember and recognise their targets.

Griffith University behavioural ecologist Dr Darryl Jones said that while most magpies are sedate, a small handful "just attack everybody".

"Only around 10 per cent of magpies attack, and of that about half of them target pedestrians. The remaining half go for either cyclists or posties and there's a very, very small group of magpies that just attack everybody," Dr Jones said.

Mr Clark is confident the data, compiled by members of the public, is accurate. To be sure, he personally approves every report to verify the authenticity.

Attacks mostly occur in spring when the birds are mating and the males are protecting the nest. "They have a big boost of testosterone so they get protective," Mr Clark told Fairfax Media

"We've had all kinds of injuries – gashes to the head, next to the ear. If you have a helmet on they might come under it."

He's even heard of cyclists crashing and suffering broken limbs from a magpie attack. 

"If you're on your bike and you do get swooped, then just get off your bike and walk past – you'll want to walk pretty swiftly though," he said.

The birds have a long lifespan, and long memories.

"Scientists have found that they actually remember people and faces and actually attack the same people each year, which is not good if you have one in your front yard."

But he has received some cunning advice from fellow magpie victims: "Befriend the birds. Feed them so they don't see you as an enemy."

"I got swooped back in 2013 which spurred me on to create the website.

"I got swooped last Friday. It collided with the helmet a number of times. There was no warning, it was a swift peck to the helmet then it continued to attack other cyclists up the road.

"Try to avoid them if possible, that's the idea of the website."

According to his website's statistics, around two-thirds of reported attacks  come from cyclists.

"They do seem to make a beeline for cyclists."

But there is one group of commuters who appear to be safe: "They don't seem to go for cars. They're not stupid!"