When bird breeding season starts in spring and angry magpies start indiscriminately swooping at the innocent - kids, dogs, cyclists - Canberrans may be left wondering whether Hitchcock's nightmares came true.
One black-and-white bomber has already claimed a scalp in Gungahlin according to the website Magpie Alert.
User Geoff Barnes recorded an injury when walking to work two weeks ago, with the magpie drawing blood despite his wearing a hat.
The website has recorded 38 attacks since early July.
In the city, one tenacious Collingwood mascot - or maybe multiple magpies - have set up shop on Bunda Street near the Canberra Centre, with five attacks recorded on cyclists since late July.
ACT Parks and Conservation's ranger in charge, Simon Stratford, said magpies could get protective of the area they were nesting in.
"Magpies start swooping during breeding season," Mr Stratford said.
"It's generally the males that do the swooping. Basically their testosterone goes through the roof."
But it's not just magpies out for blood, but currawongs, peewees and plover birds.
Mr Stratford said he had seen some pretty aggressive peewees, or magpie-larks.
"We've had a couple of incidences of people going to hospital with injuries from peewees or magpies," he said.
He said he had seen peewees stopping people from using outdoor eating areas.
Mr Stratford said currawongs, which resemble magpies except their white feathers are only around the tail, didn't show the consistent hovering magpies did.
"Currawongs are bigger and come at you from long range," he said.
"Peewees, they creep up on you a bit more."
Plover birds nested on the ground and once they swoop they'll come at you faster, Mr Stratford said.
He warned Canberrans not to panic when they were swooped, especially if they were cycling or walking near traffic.
"One of the big risks is some people do get quite frightened by swooping birds. They tend to lose their concentration, we just encourage people to stay as calm as possible," Mr Stratford said.
The ACT government website said Canberrans could expect to be swooped from July through to December as birds build nests, lay eggs and raise their young.
The Magpie Alert site adds the following:
For more advice on dealing with swooping magpies call Access Canberra on 13 22 81.
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