That's "clear" as mud.

Canadians aren't having fewer children because "aliens" are taking their jobs.  Canadians are having fewer kids because people want smaller families, or no families at all, a trend that has been observable since the end of the Baby Boom and the onset of the sexual revolution and the modern women's rights movement.  The availability of reliable contraception and birth control measures, women's entering the labour force en masse, and the general cultural shift away from people needing to get get married and have children for social reasons, determined that.