I did a lot of research on this topic a few years ago. My pond is above-ground made from railroad timbers. For several years, when it got really hot out, I would see yellow jackets (didn't know that's what they were then) around and they would single me out and attack. One bit swelled up my entire leg, I must be extra-sensitive. I couldn't go out in my yard for awhile I was so afraid. Yellow Jackets are bright yellow and black striped and they do not have dangling legs like other wasps. Also, the yellow jacket has a smoother sleek body than a honeybee. Honey bees do not have the distinctive yellow/black stripes, they are more fuzzy and the yellow is more orange. Larger "bumble" bees are also fuzzier. The yellow jackets seek and attack. Honeybees and european wasps (or maybe they are called hornets?) do not sting unless extremely provoked.
Here's a good article:
http://www.coopext.colostate.edu/4DMG/Pests/whatis.htm
This is 100% based on my experience of dealing with these in the yard. Anyway, the yellow jackets build a paper nest, like a wasp nest, but they hide it, they LOVE to build in railroad ties, they also build them in the ground. They live where they can find water and food. I hear they love garbage but I think the pond water and the hiding place for the nest is what brings them to ponds in your yard.
I have hornet type wasps that build nest in the open, on wood like inside our wood shed. They NEVER EVER bother me. They just go about their business. I have a lot of honeybees, too. They never bother me, even if I brush up against a flower they are on. But yellow jackets? I would dynamite them. They are just so aggressive.
I agree with some of the other posters, they go dormant at night so are "sleepy" in the early morning/evening. The way I used to take care of them was to go out in the early morning and wear head to toe long sleeves, closed toe shoes, long pants, gloves, hat. Cover your body as best you can. Use the can of spray that sprays 25 feet. Since it's near the pond, if you do it in early morning and cover yourself, you can use a spray that allows you to get closer. They will come flying out but will be disoriented. I haven't been bit doing that but I did have a boyfriend years ago who thought he would do it in mid-day and he got bit.
Also, I keep one of those yellow jacket traps. They really work well and they don't attract honeybees. It's just a yellow plastic container and you buy the pheromone that attracts them (do NOT get this on you though) and put it on some cotton in the container. They fly in and can't get out and die.
One good thing I noticed. They will never make a new nest in an old area where you sprayed them. I haven't had a next in my yard for a good 6 years or so. Not sure why but thanking my lucky stars.
Here's another ID page:
http://www.bees-online.com/BeeWaspID.htm
Sorry about your pup being stung. Hope all is well there.
