chain migration
n.— «Demographers have a name for it: chain migration. “People who live near each other share information about where to retire, where to vacation,” said Lance deHaven-Smith, a professor of public administration at Florida State University in Tallahassee. “They tell their friends and neighbors, and then they end up in the same place.”» —“Snowbirds Flock Together for Winter” by Julia Lawlor New York Times Feb. 2, 2007. (source: Double-Tongued Dictionary)