If you had a frame or 2 of brood, you could add them to the box on the top. Ray Marler told me this, and it has helped me find queens if i needed to. The different smell of the brood will make her come investigate and claim it as her own....has worked for me 99% of the time if i have to question a queens presence.....this could draw her up. I generally wait about 5 minutes before i look....and most of the time she is there!