There are tracking numbers for USPS depending on the service you use. I always request USPS Global Express,Global Priority or Insured Mail Int'l depending on size and value. Never a problem.
Problems with shipping to Canada
I checked the Forums but this topic doesn't seem to have been addressed before so potential shippers to Canada take heed. In June I shipped an item to Canada by FEDEX where the buyer had agreed to pay shipping and be responsible for paying the import duties. However FEDEX has been unable to collect the fees from the buyer and have informed me that as shipper I am ultimately responsible for payment. Luckily the amount I'm out of pocket is not large ($120) but I just wanted Agoner's to be aware of this possible pitfall especially if shipping high-value items