There are jobs these days that many so called "americans" won't do.. or at least won't do for a wage that is reasonable to the job.
They have found that it's easier to live on welfare, than to do these strenuous, or dirty jobs.
While I dislike illegals, many of the immigrants coming to this country have no such problem with working hard, or doing a job that might get them dirty, stinky, etc.
I wish we would control our border. I also wish we would force the lazy slackers who are riding the welfare system back into the work force. If we did, we would have far less need for migrant workers.