Bird dogs, dogs bred to HUNT birds, are pretty much hard-wired to want to take birds in their mouths. That's just their nature. Hunters use that genetic desire to get these dogs to bring game birds to their hand after the hunter has shot them. It saves the hunter lots of leg work, and in the case of duck dogs, keeps the hunter from having to go into the cold water after a downed bird. It does not necessarily make them blood-thirsty killers of birds.
This skill-set is very useful to their hunter partners, but it's a whole different skill set from being *protective * of birds. It's kind of like asking if a skier or swimmer would make a good brain surgeon. I mean, a skier or swimmer MIGHT be a brain surgeon but that would not be my first criteria for choosing someone to operate on me. Certain breeds are genetically designed to be protective of property and to herd things. Others are not. Some individual dogs can do amazing things, and just like humans, some can't be trusted to look after your socks. Sometimes you luck out. Also just like people, a dog is a dog whether it has a pedigree or not. Good luck, hope you find what you're looking for! I'm loving these stories, by the way, let's keep 'em coming!
Edited to correct minor spelling/typing errors.