No (though I'd suggest less atypical than you might think), but that's the point.
If you're looking to model migration patterns and you have a data gathering system that biases your data to capture a bimodal migration pattern - childhood in one location, adulthood in another - then I might suggest that you'll disproportionately find the data you were apparently expecting which fits that pattern.
If you're looking to model migration patterns and you have a data gathering system that biases your data to capture a bimodal migration pattern - childhood in one location, adulthood in another - then I might suggest that you'll disproportionately find the data you were apparently expecting which fits that pattern.