There are three possible jurisdictions. The first is Oregon. All parties were present and living there at the final separation and at that time the parents appeared to have decided to stay there indefinitely. Secondly, Ontario is a possibility as the child was born there, is a Canadian citizen as his father, has lived in Ontario for the first five months of his life and is present in Ontario now. Thirdly, there is Michigan where the parties own a home and have recently lived.
Jurisdiction is where the child is habitually resident.
That phrase is defined in the Act. My reading of the definition and applying it to this case is that the proper jurisdiction is the residence where the child last resided with both parents before the father acted unilaterally. That clearly is Oregon. It may be of interest to examine the professed intention of the parents. Here the mother clearly wished to stay in Oregon near her family.