Just curious, have you scouted this area at all? This is why it is so important to locate preferred feeding areas and strut zones. If you can't get him in in the early AM, head him off at the feeding area. If there are any areas, like along the field edge where the hens may start nesting really soon or them to dust, that would be a good set-up for middle of the day. Sounds like he had company that was trumping your calls.