I have had a high degree of success in keeping turkeys out of my garden beds by turning a portion of my yard into a turkey playground, i.e. a carpet of mulch with a central mound. The birds seem content playing king of the castle for much of the time they are in the yard.
There is also a section reserved where a particular seeded grass grows (I suspect native - and possibly one of their traditional/original/native foods) the birds preen the stems of this grass regularly, and ignore everything else to get to it.
As noted by Hajkowicz, the bird seems reasonably intelligent, and through stern conversation, I have appealed to its intellect and instinct for self preservation, i.e. a threatening stance, followed by you don't eat my tomatoes and I won't eat you, OK?
I also converse with the birds regularly imitating their calls to each other. As mad as it seems, I am an avid grower of all things native with the odd exotic here or there.
If one is not opposed to more radical interventions, try a kilo bag of either dried chilli flakes or powder from your local Asian foods supermarket, scattered liberally over designated no go areas as a robust line of last defence, or is that offence?