Ive eaten most of these, the reason they are tough is because they are wild and use their muscles lots, the local bushturkey or Wowan (Alectura lathami) around my parts is wormy as, but mostly in the gut, I have seen worms crawl from dead turkeys as the bodies cool, Fla, vour as with just about any meat depends on the time of year and the seasonal foods the animal is eating, even freshwater fish get that slimy dirty taste as the water dries up around them.
The Bustard (Ardeotis australis) is also tough but has a much better flavor even in the dry season, I reckon the key to cooking all these birds is low heat and long cooking times , a ground oven and wrapped in paperbark to seal in all the juices really helps to tenderise the meat and also keep the flavour in.
Pull off all the feathers you can then scorch the rest from the body over a hot fire but dont let the heat start to cook the flesh too much, , leave the gut's till last, though normally they are left in, I dont like offal personally but it is a personal choice, in the case of Magpie Geese (Anseranas semipalmata) and also Bustards the crop tho can often contain some nice fruits and herbage that can really add to the flavour of the meat. If you want to keep the crop you need to feel for it and make an incision underneath it, otherwise before gutting just chop the head and neck off close to the body of the bird.
Once you have plucked and scorched off nearly all the feathers and down from your bird cut around the cloaca (poop shoot) with a large enough incision to fit your hand but dont cut deep just cut the lining of the gut, and then gingerly reach in with your fingers first so as to peel the guts from the body cavity, it's not hard it,s just a matter of separating the holding tissue from the wall of the gut, just like with a fish but by feel rather than by sight. It,s just the same as you would do with a chicken and the whole lot should come pout in one neat ball as long as you have separated the crop or head.
Next up is the cooking preparation , chuck in whatever you like, Onions , Garlic, Native pepper, Akudjura, Lemon myrtle , Salt, whatever but the key is the sealed slow cook, Hungi, cutmurray, call it what you want , wrap the bird in something that will seal in the juices of the bird and the seasonings, paperbark (the nice clean inside bark) taro leaves, even those roast bags you get from woollies or coles.
Make sure that your ground oven is not too hot, you want a nice slow cook and too much heat to start will only make an already tough feed tougher.
Personally, Wowan the scrub fowl is the bottom of the list for me, they aint real picky with their diet and it shows, Wormy , stringy and bitter most times, Bustard has a good flavour, plenty of meat, good eating if cooked properly and really tasty when fed on the local farmers lucerne crop, UMMM so someone told me....But for a great feed full of flavour and juicy mouth watering taste go get yourself some EMU. It truly is up there with the best bovine Rump roast you can get. Ive eaten most of the wildlife in this country from flyingfox to frilled neck lizards , Goanna to Gecko's, Barramundie to Betel's but Emu is just the Dendrocygna eytoni's testicles in my books.
"Such is life"