Some of my favourite clips of Tumblers/rollers/divers.

https://www.youtube.com/watch?v=R8TP6OoC-oM&feature=channel_page

Like how he fools around at 1:16 on this vid.
https://www.youtube.com/user/pigeonsport#play/uploads/31/qaqiASY2PIg

Listen for the fake gunshot and watch this bird dive/roll/tumble when it sees the dropper, wow!
https://www.youtube.com/watch?v=6eCxeaW2acY&feature=channel_page

https://www.youtube.com/watch?v=lkG9MsCAuGI&feature=channel_page

https://www.youtube.com/user/pigeonsport#play/uploads/15/gvEZPUDIsjU

https://www.youtube.com/watch?v=v2tjM_tiagg&feature=channel_page

https://www.youtube.com/watch?v=AXReeNl0Ny4

Chill out to this one :it's all good:
https://www.youtube.com/watch?v=-XblwfuSiDg&feature=channel_page

Just some of the many talents of the wee doo. Hope you enjoy Thumbs up