Good advice you have gotten, Lisa. I have heard that if YOU go out in the back yard and front yard, and sit on the ground, take a book or something, and just sit....you might 'find' Pete. Running around, calling for him, is possibly going to scare him. The calmness created by you sitting in the yard, and every so often calling out for him, plus, the quiet of sitting out there, might help.

Good luck.