I shamelessly copied this off the GA forum. :)
Its the mirrors what done it little maties – aye – the mirrors. However, more than a simple mirror is needed. Here`s what worked for me – I hammered a 2 metre pipe down the centre of the mound and into the ground level soil so it was good and solid – I made a box out of junk chipboard roughly 400 m.m. on all sides and taped two mirrors to the opposite sides, cut a hole in the top and the bottom of the box with a hole saw and threaded the box onto the pipe. The turkey became consumed with competitive hatred against the image of himself in the mirror and slowly demolished his own nest in a lengthy fit of rage against the mirror machine. As he dug out the top of the mound the mirror box slid slowly down the pipe, thus staying neatly perched on top of the shrinking mound. This worked much better than a single flat mirror, since the bird seems to eventually figure out that there cannot be a real bird behind a flat 2 dimensional object. But with a box, he remains convinced that the competitor is behind the box and sometimes shows his face (on the other mirror). The turkey will complete so many laps of the box and attack the box and mirror so relentlessly (days) that the mound is eventually destroyed by his own hand (foot) and your garden then seems to be blacklisted by the turkey community generally for evermore. Your yard becomes their heartbreak hill. While this is mound-centric battle is raging there is no garden demolition happening and no mulch raking, so long as you let the initial mound be built (possibly even with your help to minimise their raking efforts). I submit that this method is utterly successful and legal since it does not actively harm the bird, apart from possibly inducing extreme depression, frustration and low self esteem and possible ridicule by females unimpressed with his mound building skills and inability to see off a competitor. To our shame we set up a lounge chair just inside the screen door to sip cocktails and watch this epic transformation from strutting invincible master of the universe to mere shadow of former turkey when victory was finally ours. Yes, we did the chilli thing, the dog thing, the talking teddy thing, sprinklers, chicken wire, you name it, everything previously mentioned on all forums, to no avail. Spend a half hour and make a mirror box and live happily ever after.