Wis. Stat. § 822.06

(1) A court of this state shall not exercise its jurisdiction under this chapter if at the time of filing the petition a proceeding concerning the custody of the child was pending in a court of another state exercising jurisdiction substantially in conformity with this chapter, unless the proceeding is stayed by the court of the other state because this state is a more appropriate forum or for other reasons.

(2) Before hearing the petition in a custody proceeding the court shall examine the pleadings and other information supplied by the parties under s. 822.09 and shall consult the child custody registry established under s. 822.16 concerning the pendency of proceedings with respect to the child in other states. If the court has reason to believe that proceedings may be pending in another state it shall direct an inquiry to the state court administrator or other appropriate official of the other state.

(3) If the court is informed during the course of the proceeding that a proceeding concerning the custody of the child was pending in another state before the court assumed jurisdiction it shall stay the proceeding and communicate with the court in which the other proceeding is pending to the end that the issue may be litigated in the more appropriate forum and that information be exchanged in accordance with ss. 822.19 to 822.22 . If a court of this state has made a custody decree before being informed of a pending proceeding in a court of another state it shall immediately inform that court of the fact. If the court is informed that a proceeding was commenced in another state after it assumed jurisdiction it shall likewise inform the other court to the end that the issues may be litigated in the more appropriate forum.

(4) The communication between courts called for by sub. (3) or s. 822.07 (4) may be conducted on the record by telephone conference to which the courts and all counsel are parties.