I don't know the answer, but have a similar situation. I'm in zone 8or 9, not sure which, and have hundreds of bees in an elm tree, not bunched up like a swarm but grazing along all the branches. There are 4 or 5 wookpeckers and some butterflies, too. I see water or sap dripping from the leaves when the light is right. That would explain the bees, birds and butterflies, but not what is causing the sap to run. that happens in the spring, last I heard. Any thoughts?
Norm

I have 2 large trees that attract bees by what seems the hundreds. These are probably not africanized bees, most likely just native honey bees which are far more interested in their "work" then you. I am constantly brushing up against the foliage of my tree and the bees just move around me. Bees are a natural part of any garden, as are butterflys. They are doing your garden a great justice by pollinating. Enjoy these wonderful little creatures while they are visiting, or at least learn to because there is nothing that can be done to convince them to leave short of removing the tree!

A note on African Bees, while they are impossible for a non expert to tell apart from native honey bees you can watch their their behavior for clues. Be alert for bees that are acting strangely. Quite often bees will display some preliminary defensive behavior before going into a full-fledged attack. But do remember not to panic at the sight of a few bees foraging in the flowers. Bees are generally very docile as they go about their normal activities.

You can also help prevent honey bees from building a colony in your house or yard, fill all cracks and crevices in walls with steel wool and caulk. Remove piles of refuse, honey bees will nest in an old soda can or an overturned flower pot. Fill holes in the ground. If the bees are just working and have not colonized in your yard they are even less likely to care about you because they have nothing to protect.

Hope this info helps you feel more at ease!

Acacias attract bees. It's natural - they have a sweet sap.

What to watch for is bees entering and leaving a crack in a house or wall: that's a nest!

I used to keep bees when I was younger and before the africanized bees became a problem. You can look around your yard for the bees but likely they are off your property. I have seen swarms in trees, in houses, under the eaves, water meter boxes, electrical boxes, etc... Bees can travel several miles looking for a souce of nectar and when they find it they will let the other bees in the hive know the location. I too have had them all over my acacia saligna that has been in bloom the past couple weeks. You can hear them from the other side of the yard. Like lazygardens stated, watch to see if there is a lot of bee activity around the house or other non-plant objects. Good luck.

I've had a couple of hives try to start up in my yard. Believe me you WILL know when they are a problem! Sometimes they just are resting in a mass around a branch while looking for a new home but I was lucky enough to not have them move on TWICE! The mass just stayed and they swarmed by thousands around the tree. They were just honey bees but still that's just too many! So almost $400 twice to remove them. When you are near a bees nest, especially African the scouts will bump up against you and keep flying at you. Whatever you do DO NOT HIT them or you will be covered in bee pheromone with a big target painted on you. They sounded like distant plane coming in for landing when the whole hive landed to begin with! Of course this happened on a Friday both times and we had to wait until Monday or Tuesday for the exterminator, we couldn't go in the front yard. They do love mesquite trees too!

I had cause to have a swarm removed by an experienced bee keeper here in the Hi Desert of Ca. He told me that all bees in the South Western US are now considered to be Africanized. He said each year he replaces the queens in his hives with queens from the Pacific Northwest. Fortunately the day he came out it was cold and the swarm wasn't very aggressive. He clipped off the branch they were swarming on and placed it in a box. Taped it up and took it with him.

Some years ago I had groups of dead honeybees at my back door on the patio. I couldn't figure out if they were attacking my cats, who rolled them off or what. Later I saw maybe 10 bees flying near a vent at the peak of the house. I got up in the crawl space and found several long honeycombs hanging from the ceiling and hundreds of bees. I got a bee guy out to remove them, and he said that he's seen combs like that drip honey that eats its way through the ceiling into the house. With honey, the combs he removed probably weighed 15 lbs. I couldn't believe all that was going on up there with so little activity in the yard. After that I screened the vents and haven't had any problems since.