If I was as knowledgeable as you won't have to ask questions
I saw a long mark thrown once that several dogs ran.. it was thrown out of cover, and onto bare ground.. Very few dogs would hunt the dirt.
Yes I like to see dogs deceived by having a white coat set out deep of a short retired mark,, seems to happen all the time in field trials and hunt tests have their own version of the concept..
Don't get me started on hen pheasants,,, but I am cool with those and have a pen full of them even though my dogs never see them at a hunt test or at the MN. They teach amazing marking when formatted properly.
Whenever I get the opportunity to train on birds thrown onto islands I take advantage.
Can't get enough of them in training.
I would have thought Angie would have noticed that there is only one station with at least two white coats (#4) and that it is a huge huge throw for a dead bird.
I do think Barrier birds are a hard concept at times, and subtle angled cover is great at gently pushing dog up wind of mark.
I was taught that good bird placement is putting the bird where a dog wouldn't naturally/normally want to go. And I'll say that experience is the best teacher of that not necessarily having a set list of things. Watch as many dogs as you can run anywhere and sketch the setup and not where they went. Over time you'll learn patterns that will guide you as to what good placement is.
Good bird placement is intimately related to terrain, wind and gun station interactions. Change any one of these and a well placed mark becomes a give away. All of the examples listed are great concepts to train. Simply picking one will get you started but to really place a bird all factors have to be considered.
The simplest way to learn is to train with someone better than yourself and pick their brain during set up. This is the fast track and will get results quickly. Experience is the key.
When I first started, James Spencer's book gave me a big head start on mark placement. Before reading it, I simply threw lots of marks with little regard to anything but the wind. Now 6 years later I am beginning to truly understand how little I actually know.
Keep working at it and you will improve.