“The mangoes nearly killed us,” said Julie McKenzie with a smile and a celebratory sundowner drink in her hand, recalling the backbreaking 10-hour shifts harvesting tropical fruit in northern Australia.

For the past few weeks, the 60-year old grandmother has been working alongside her 64-year-old husband, Ian McKenzie, picking grapes in the heat of summer in the New South Wales Hunter Valley.

The couple from the port city of Newcastle, north of Sydney, are grey nomads, a growing cohort of older Australians who have swapped the comfort and familiarity of the suburbs for a life on the road following the fruit-picking trail.

The exact numbers of grey nomads crisscrossing Australia are unknown, but academics have estimated there are tens of thousands constantly on the move, and around a quarter of those have sold their homes. For some, trips away can last for a few months, while others travel indefinitely. Unlike itinerant snowbirds in North America, who travel south in recreational vehicles to escape the winter, Australia’s wandering retirees do it year-round.

“It is quite a phenomenon,” said Tim Harcourt, an economist at the University of New South Wales Business School. “Retired people don’t want to stop working. They want to combine a bit of fruit picking, a bit of leisure and a bit of travelling in their retirement. There is actually a shortage of people needed for fruit picking, so having these experienced workers is a really good thing,” he said.

In other corners of the world, including Spain and Sweden, the fruit picking industry is beset by poor conditions and meagre wages, and often involves unskilled migrants or illegal immigrants. Australia, too, has its problems, especially with unscrupulous operators ripping off backpackers, but the nomads have an informal network that helps them weed out corrupt outfits.