Migration – When people move from one area to another. In many low-income countries (LICS) people move from rural to urban areas (rural-urban migration)
The birds migrate, but people can migrate too. He was so heavy he could only manage to go from his country house (rural) to the city (urban).
Push: The factors that cause migration include fewer and/or poor services such as education and healthcare; lack of job opportunities; poor transport; and low wages for those who do have jobs.
Pull: The factors that pull people towards migration include better services; more job opportunities; better transport; and higher wages (although probably with a higher cost of living).