Research suggests that birds may use quantum effects to navigate when migrating to warmer climates.
Although data surrounding labour migrants varies it is clear that apartheid-era patterns persist, writes Lisa Steyn.
"Johannesburg has a lot of soul, a lot of culture, a lot of South Africa," says Azra Joosab, who moved to Johannesburg at the beginning of 2008.
The scale of urbanisation in South Africa, which has seen millions move to informal settlements, was highlighted at a government briefing on Monday.