hbj,
I have a bit of spare time & a fresh cup of coffee so I will try to answer most of your questions in one hit -
They are looking for someone who knows how the cattle will behave when confronted by a man on foot, horse, motorbike or helicopter. You need to anticipate what the mob will do & make them do what you want, & you need to do it without stressing the cattle more than you have to. You need to decide if you are going to push the mob or let them go where they want to & take them the long way to the yards. Do you push them out of the river & take them cross country or do you muster them into the river & follow it? You need to be able to decide how much time you should spend trying to get an old cow out from under a tree while the rest of the mob goes wild, after all how much is she worth to the owner? What if it is a bull under the tree, is it a scrub bull that needs to caught or a herd bull that can stay in the paddock? Do you leave a scrub bull if you can't get it or do you call in some ground help? If you have no ground help do you leave the bull & tell no-one or do you shoot it? If you don't have a gun do you think you could find that bull again later in the afternoon if you come back with a shooter? From where you last saw the bull which direction is he most likely to go once you leave him? You may be on your own or you may have 3 or more other helicopters with you, you may have any number of horsemen, motorbikes, bull catchers, trucks etc on the ground to assist, & they sometimes rely on you to guide them to where they are needed, & they need to be there before they are needed. They may have to travel over some pretty ugly country, so your anticipation of what the mob will do will allow you to get them in position in plenty of time. You need to plan ahead based on the terrain you need to cross. Not everyone on the ground will have a radio, but there is a pretty good chance they know what needs to be done & if you start doing something unexpected with the helicopter the whole day can turn to ****. If what the ground crew is doing isn't working or hindering, you need to change it & tell people where to go & what to do. The helicopter pilot has a birds eye view & you need to be working very closely with the head stockman on the ground. If he respects your knowledge & ability he will have his crew move the earth to help you & get done what you need. If he doesn't you may as well go home. You need to speak the language of the people on the ground, because if you tell them "there is a cow under the tree" it had bloody better be a cow, because if it's a pissed of bull they might want to know that beforehand. What sort of tree is it? There's a lot of trees in parts of Australia, & so they know where you are talking about you might want to know the difference between a gum tree & a Bauhinia tree.
Most cattle in Northern Australia have been mustered with helicopters for quite a while now, so they have built up a knowledge base on how to evade capture. If you haven't built up that same knowledge base so you can prevent them from evading capture then it isn't going to be a fair fight. You need to be confident in your decisions regarding the cattle, because you can spend all day & end up with 1500 arseholes looking at you from the mob & in the blink of an eye you have 3000 eyes looking you & they're running under your helicopter faster than you can count them. You can fly around like a wounded banshee trying to get them all back together again, but you need to know when to call it quits & go home. No doubt the cocky(pastoralist) will want to know why he has a bill for 10 hrs of helicopter time & no cattle in the yard, which is where the confidence in your decisions comes in. Cattle are not domestic pets, & sometimes even the best mustering pilots lose a mob for various reasons & regardless of who is to blame it is never a pleasant experience.
Different breeds of cattle behave in different ways. You need to know the difference between a hereford & a brahman, & you need to know how long to persevere with a beast if it is misbehaving. Some animals can be persuaded, but a pissed off brahman cow will pull your helicopter from the sky as she runs underneath you. You need to be able to tell from your helicopter how the cattle are handling the walk. If they are tongueing(imagine your tongue after running a marathon for an explanation of this term) after the first 5 miles of a 15 mile walk then you need to change the plan, as the current one isn't working.
I could go on for many more pages, but suffice to say that I haven't yet spoken about the flying skills needed for mustering. That alone should highlight the point that many other experienced mustering pilots on pprune have said ad-nauseum - Mustering pilots need to have experience on the ground so they can operate effectively in the air. If you want to do it, follow the advice of others & get a job on the ground. If you're good you'll get flying, if you're not you won't. If you meet a mustering helicopter operator over a campfire in the bush while you covered in dust & **** & ask for a job you have a lot more chance than if you walk in to the hangar with a clean shirt & flowery resume in your hand.
Time for another coffee.