Birth rates and border crossings

"We use census data for the US, Canada, Spain, and UK to estimate bilateral migration rates to these countries from 25 Latin American and Caribbean nations over the period 1980 to 2005. Latin American migration to the US is responsive to labor supply shocks, as predicted by earlier changes in birth cohort sizes, and labor demand shocks associated with balance of payments crises and natural disasters. Latin American migration to Canada, Spain, and the UK, in contrast, is largely insensitive to these shocks, responding only to civil and military conflict. The results are consistent with US immigration policy toward Latin America (which is relatively permissive toward illegal entry) being mediated by market forces and immigration policy in the other countries (which favor skilled workers and asylum seekers, among other groups) insulating them from labor market shocks in the region"--National Bureau of Economic Research web site.