Be on the alert for magpies!

It's not the buds attempting to bloom, or the leaves unfurling on the branches or even the scent of jasmine in the air that truly heralds the arrival of spring. It's the squawk in your ear, the beating of wings around your head, the flash of a frenzied black and white body and the quick peck of a beak near your ear - magpie season and the return of spring go hand in hand.

At this time of the year magpies are the perennial pests of cyclists, walkers and joggers alike. I have seen walkers hide a stick in the shrubbery so they can pick it up when they know they are entering magpie territory, and wave it around their heads in an attempt to ward of any flying attack. Then when they consider the area 'safe' they deposit their weapon in the bushes to collect it again, and repeat the defence manoeuvrer on their return along the path.

Magpies attack between August and November, which is their key nesting period. Male magpies are mainly, but not exclusively, the attackers. Extremely aggressive magpies may land in front of people, who they view as threatening their nest, to attack them front-on, although this is rare. Magpies are aggressive only during the breeding season when the male is protecting chicks.

The breeding season and associated aggressiveness correlates with the growth of the testes in the male magpie. Their testes become enlarged and testosterone pumps through the male's body. The rest of the year the testes shrink and testosterone levels are lowered.

For cyclists, carrying a big stick as a defence against magpie attack is not an option. Some success has been recorded with attaching a flag on the end of a pole to your bike. Magpies nearly always attack from behind and the height of the flag is said to distract the flying magpie from your helmeted head. But attaching the flag-flying pole to you bike can be problematic. Most road bikes are not designed for such accessories.

Some people swear that applying fake 'eyes' to your helmet scares the living daylights out of attacking magpies. It has been reported that the magpie missile sees the 'eyes' as a threat and backs off immediately. Others say the method is only as effective as the aggression level of the bird! But who wants to wear an ice-cream container with eyes painted on it on their head! Attaching your sunglasses to the back of your helmet may be a better proposition.

A loud horn has also been reported as being effective - but by the time you realise that you are under attack and reach to sound the horn, the danger period is over. The magpie has either been successful and you are now sprawled on the road or the attack was thwarted by other means.

Interestingly, most magpies which attack pedestrians attack the same few individuals over and over again. If they attack others, it's probably a case of mistaken identity, said Dr Darryl Jones from the Suburban Wildlife Research Group at Griffith University. He believes such magpies may have had an early traumatic experience - perhaps someone who looked like these people had harmed the magpie chicks, or even 'rescued' a fledgling, something the parent mistook as predation. Magpies are able to recognise and remember individual human faces, even if the person wears different clothes!

The best way to avoid being attacked by a magpie is to avoid entering nesting areas while the young are in the nest. If a magpie attacks once, avoid the track or take an alternative route for several weeks (chicks remain in the nest for around four weeks after hatching).

Throwing objects at the birds will only aggravate them further and make them more aggressive. Remember, the bird is defending its young.

It has been suggested that the continuous movement of a cyclist riding a bike could be a reason for magpie attacks. It has been shown that if the rider dismounts and walks with the bike, the attack halts instantly. Perhaps an opportune time to get off your bike!