There is a training exercise that I have found very useful in preparing the Wildrose advanced and finished dogs to line on doubles. It's called circle memory doubles (CMD). This exercise is a modification of circle memories.
The goal of CMD is to teach the dog to hold a straight line to a bird or bumper despite the interference of factors, distractions or influences. The exercise also improves the dog's memory as an added benefit much better than double-marking drills could produce.
Another benefit of this exercise is that you don't need a great expanse of training grounds or any expensive launcher equipment. You can run this entire drill, without assistance, with only six bumpers. We do need an area that allows the inclusion of varied terrain, ground cover, woodlands or a water source like the backwaters of a pond. Any type of cover located in or around open fields that would provide an area to hide bumpers requiring the dog to hunt.
We begin by salting one area of cover in the open field with three feathered-covered bumpers. These are memories, so our dog is at heel watching carefully. Heel your retriever away and circle around to your next area of cover, perhaps 40 yards or so away. Salt this area with three bumpers. I try to incorporate a marsh or water as one of the two areas. Continue to walk away in a circle pattern around both targets (salted) areas.
Remember, this is a memory lining drill. Your student knows the location of the bumpers but the dog's perspective is changed with each position as we circle the two salted areas; a much more effective strategy for improving lining than standing in one location.
Think of CMD as an ever-widening circle around the two target areas. Your retriever should be running increasingly longer distances with each retrieve, often passing directly by the closer grouping of bumpers as you line for the longer bumpers.
As always, practice retrieving the longest bird down first, even if the dog must pass a closer group. On a hunt, it's that long bird that will likely be lost while the retriever ops to pick the closer bird.
As we circle the circumference of the area, with our student at heel, we alternate the selection of areas focusing on the target at the longest distance. As we circle we will incorporate lots of varied terrain, different types of cover and other distractions our dog must overcome to hold a clean, straight line to the bumper area. Additionally, I expect the dog to:
Drive out hard with enthusiasm. The memory helps to promote this behavior.
Demonstrate a hard hunt of the salted area.
Punch straight through cover and overcome any barriers or distractions encountered along the line.
If your dog does not take a straight initial line to your intended target or pulls off the extended line as he drives out to the bumper, perhaps to switch to the other salted area or to avoid cover or a barrier, stop and recall the dog. Realign and re-send for the correct bumper area.
Circle memory doubles are easy to set up and they are very effective training exercises that can be set up in a variety of interesting locations. All you need is your retriever (one under control on the whistle and hand signals), six bumpers and your hiking boots. You are on your way to improving your dog's lining skills for doubles or marks. And as an added bonus, you can skip the gym that day because you will get a nice work out to boot!