When bees drift, they leave one colony behind and move to another one nearby.
Sometimes this is accidental. A foraging bee returning home may accidentally enter the wrong hive. Since she brings pollen or nectar with her, she is welcomed instead of being viewed as a robber bee.
Drifting can become a problem when more bees drift one way, leaving one colony short of bees while the other colony can become overcrowded.
If bees are leaving a colony where there are pests, mites and disease, they will take these to their new hive. Accepting drifting bees can harm a healthy colony. This is a serious concern these days, and probably the biggest reason drifting should be curtailed.
When bees drift from a stronger colony to a weaker one, they can give the weak colony a needed boost with hardy worker bees.
Drones tend to drift much more than worker bees.
What you can do to deter drifting:
If your garden apiary has more than one bee colony, placement of the colonies can make a difference to how much drifting goes on.
Which way do your colonies face? It is best for them to face in different directions. The entrances should be angular or opposite to each other.
Use bright pastel colors on your hives to help bees know where to go. They may not have the sort of color vision humans have but they can differentiate bright colors and are color-aware as we know from all the vibrantly colored flowers they pollinate.
Place a colony near a statue, tree or bush so the resident bees identify it as home. This, like colors, can help them with navigation orientation.
If you have several colonies all in a row, try changing out the direction of every other colony. You will have to work both sides of the row. It might also be helpful to arrange them in an outward facing circle.
Colonies in the middle of a row are more likely to lose bees and colonies on the ends of rows are more likely to gain new bees and produce more honey.
If most of the drifting is one-way, change out the locations and put the colony that is losing the most bees into the place where the popular colony is. It might balance the numbers out a bit better.
Have you got any drifting tips to share?