Thank you all for the recommendations and advice -- what a tremendous resource this list is! For those of you who expressed concerns about exterminating bees, rest easy: our pests were yellow jackets and we had 2 active hives (one in the ground and one in our rock wall). We had Jim, 'the bee hunter,' come today and he sprayed and removed both hives. According to him, this is the worst summer he can remember in terms of these wasps and he was stung twice even while wearing protective gear. Some neighbors have requested that I post a follow-up with the information received (see below). Bee Safe, Laura & Jim ;) If aggressive, they are probably not bees at all; probably wasps or yellow jackets which do get nasty in the fall (probably because as soon as they fertilize the eggs for the queen, they all die). Yellow jackets and wasps have a very tiny waist, while bees (which we need for all sorts of fertilization) have a rounded tummy. Don't kill the bees. If wasps or yellow jackets, do it in evening when they stay in nest. I just sprayed a yellow jacket nest in my garden. If you watch carefully from 15 feet or so, you will be able to find the hole (frequently a squirrel hole, abandoned) by the in and out activity. There are issues with captive honey bees dying out, so I don't think you can "exterminate" them right now. There are companies that will capture the hive alive and relocate it. http://www.beecontrolpittsburgh.com/ You may wish to get an estimate from a guy named Ken Knight who deals with "animal services." His business card says "professional wildlife management" and I called him some years ago with a bat problem in my attic. His business card specifies bees and I believe he is experienced in many such situations. Again, his business card that I have is about 12 years old but here is the info -- Ken Knight P.O. Box 101724 Pittsburgh, PA 15237 412 - 795 - 9333 412 - 366 - 4225 412 - 221 - 4358 Jim Abraham is amazing with anything that stings! http://www.thebeehunter.com/contact.html Check out the Bee Hunter.http://www.thebeehunter.com/ Jim is great! He's quick to respond and provide service, too. 412-956-2448. Pittsburgh Bioneers has information about an active bee keeping group. Maybe the bee keepers will be interested in relocating the hive rather than destroying it. There is a shortage of bees for pollinating, so I imagine they would try to preserve the bees in a safer place. We've had Samuel Krieger eliminate bees for us several times. He's great! He is thoughtful about his use of chemicals, especially around small kids. We really valued that. We'd call him again if we needed. ECI Pest Control 412-422-6757 My friend had good luck with Kevin Abraham, "The Bee Man". 724.935.7207. We have used The Bee Hunter. See BeeHunter.com Stephan_repasky@yahoo.com<mailto:Stephan_repasky@yahoo.com> Is who I would suggest but if they are honeybees I would suggest you leave them go considering the lack of them in highland park over the last few years. They generally won't attack unless they feel the hive is truly threatened. I walk by there with my dog all the time and never had a problem. Try Burgh Bees. Here is an article I just read about them. http://www.examiner.com/x-13103-Pittsburgh-Gardening-Scene-Examiner~y2009m7d... do not exterminate the bees. contact the Pittsburgh zoo Hort department (Frank Pizzi) and ask his advice. We are trying to save the bee population for pollination reasons. without bees, we would not be. try Sani Products 412-322-5900. Call OCEAN BREEZE 412-805-5602 check out burgh bees; www.burghbees.com<http://www.burghbees.com/>. They removed hives from a building in Braddock and did not kill them. They are very knowledgeable. We use Ehrlich.