I do believe the Border Collie is the most intelligent dog. Dogs, by nature, differer in their ability to learn. Some understand better than others, some train easier than others.

That being said, I also believe our sporting dogs have been bred to hunt. It's part of their makeup and they live to hunt birds. Some take more time to train than others but for the most part bird dogs can be trained to do what they were bred to do. Plus, I could care less in how intelligent one breed is vs the other. Once they understand what they should do in the field, you will have a dedicated dog for life.