Legal Question in Family Law in California

Yes, unless he files for divorce and serves her, which would put her under an automatic restraining order not to remove the child from the state. If she removes the child before he can file, California will still exercise jurisdiction over the marriage and the child for up to six months, and an order could be obtained to return the child to California, but better not to count on that since even if routinely granted, it's not a cheap process getting the California order and then getting it enforced in Oregon.

A better start to this divorce and new relationship as lifetime parents operating in the child's best interest would be to attempt to reach a stipulation on how to proceed with parenting by enlisting the help of a co-parenting counselor. This approach may aid in building trust between the parents and remove the risk of a prolonged and expensive parenting battle. I have yet to hear of a situation turning out well where one parent unilaterally departs with the child without the other parent's consent or court orders.