An Australian bike rider died Sunday after he veered off the road to avoid a swooping magpie, police say.

The unidentified 76-year-old man was cycling along Nicholson Park in Woonona, New South Wales, when a witness saw him careen into a fence post as he tried to avoid the bird, police said.

The man fell off his bike and sustained serious head injuries. He died later after being airlifted to a hospital, police said.

Magpies, striking black and white birds, commonly swoop down in Australia, harassing people from August to October during their mating season.

Gisela Kaplan, a professor who studies animal behavior at the University of New England, told 7News that the birds swoop when they perceive an unknown threat by an intruder.

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"A stranger means an intrusion," she told the broadcaster. "Magpies are smart enough to recognize people and their habits and won't swoop anyone they've come to know and trust."

According to news.com.au, some male magpies are most aggressive in September after eggs have been laid.

Magpiealert.com, which allows Australians to self-report attacks from the birds across the country, has already tracked over 1,700 attacks in 2019, which have resulted in more than 200 injuries.

Australia's national parks service says the best way to avoid an attack is to just walk away. Often, the birds just want to send a warning, but they might strike if "the bird just doesn’t like you," the New South Wales parks service writes in a blog post.

A variety of defense mechanisms are used across Australia, including sticking cable ties and painting eyes on helmets, the park service says.

"Weirdly, magpies are less likely to swoop if you look at them, so you actually have to lock eyes with them and hold the staredown until you’re out of sight," the park service adds.

A different, less aggressive family of magpies also live in the United States. Geoff LeBaron of the National Audubon Society told USA TODAY that it is possible magpies in the U.S. exhibit swooping behavior, but he's never heard of it nor seen it happen.

"I can’t say for sure that they would never do it, but our magpies here are generally much more wary of humans than the Australian magpies," he said in an email.

Magpies in the U.S. are corvids, related to crows, ravens and jays, he said, whereas Australian magpies are related to other similar birds called butcherbirds there. Magpies in the U.S. "are often not as directly interactive with their human neighbors as crows and jays may be," he added.

Follow USA TODAY's Ryan Miller on Twitter @RyanW_Miller