From Dan Griswold, via Bryan Caplan:
The typical foreign-born adult resident of the United States today is more likely to participate in the work force than the typical native-born American. According to the U.S. Department of Labor (2011), the labor-force participation rate of the foreign-born in 2010 was 67.9 percent, compared to the native-born rate of 64.1 percent. The gap was especially high among men. The labor-force participation rate of foreign-born men in 2010 was 80.1 percent, a full 10 percentage points higher than the rate among native-born men.
Labor-force participation rates were highest of all among unauthorized male immigrants in the United States. According to estimates by Jeffrey Passell (2006) of the Pew Hispanic Center, 94 percent of illegal immigrant men were in the labor force in the mid-2000s.