Spring is breeding time for the region's magpie and plover populations, and they may attack anyone who threatens their nests.

The birds should mellow by October but, in the meantime, residents are advised to be watchful in magpie hot spots such as Figtree Oval, North Wollongong bike track and the northern suburbs.

The NSW National Parks and Wildlife Service (NPWS) receives many calls asking for help in dealing with aggressive native birds.

This spring, the service is reminding people not to provoke the birds unless you're in the mood for a nasty eye peck. Holding an umbrella or stick overhead while walking can deter swooping, and some cyclists attach cable ties to their helmets or wear an ice-cream container to ward off the birds.

Dog walkers are advised to control their pets within 100 metres of nests and to warn fellow walkers about swooping activity.

The NPWS recommends that bike riders dismount through swooping zones, to avoid falling off their bikes, and then move through the area quickly.

Anyone concerned about an aggressive bird should contact the NPWS on 1300 361 967.

The service works with councils, the Wildlife Information Rescue and Education Service and other groups to deal with problems with native birds.