Found this article from Univar, thought is was a good question and answer worth sharing:
Pest Control Question:
I have looked for this information pretty extensively, and cannot find an answer on the net, or in any reference material I have access to. How far will Bald Faced Hornets forage from their nest?
Mr. Pest Control’s Answer:
I started thinking I was going to be completely stumped on this one too, although finding no definitive answer thus permits me to speculate, which is always fun. However, I did come up with a couple of thoughts from sources that ought to know what they are talking about. One is an old National Pest Management Association article on wasps, and in this they discuss both yellowjackets and bald faced hornets, which are related to yellowjackets in the family Vespidae. In fact, at one time they were considered a kind of yellowjacket, but at some point in time were separated out into their own genus – Dolichovespula.
In this article the NPMA states that typically yellowjackets will forage within 1000 to 2000 FEET from their nest, but may travel “several” miles to find food if necessary. That is pretty wide open. In a second resource from Colorado State University they state that the Bald Faced Hornet typically forages within 1000 YARDS of its nest, which would be well over 1/2 mile. Where either of these sources got their numbers I don’t know, and I have to assume that someone has actually studied these foraging patterns of the social wasps to come up with the distances. However, what this does suggest that it’s a piece of cake for either a YJ or a BFH to fly a quarter mile or more from its nest to food resources, making it difficult to impossible for you to be able to follow those wasps back to their nest for direct treatment. Adding to this problem is the habit of YJ’s often to nest in the ground, and until you are right on top of the nest opening you may not know it is there.
Bald Faced Hornets are big and aggressive to intruders, but still are not nearly the pest problem the scavenger species of yellowjackets are. The BFH usually sticks with natural foods, such as caterpillars, while several species of YJ’s are the ones that help themselves to our outdoor food and drink occasions. Given the difficulty in locating the nests for these yellowjackets, the option of baiting for them takes on a good significance. We lost the only product we had for baiting for yellowjackets – KnoxOut 2FM – but in the last couple of years regained a good alternative, which is Onslaught from MGK. This microencapsulated insecticide can legally be mixed with some bait attractant and placed in stations for the YJ’s to access. Univar sells these stations as the Alpine Yellowjacket Bait Station, and they come labeled with a sticker for Onslaught. The foraging yellowjacket detects the food within the station and enters through pre-drilled holes. It removes a chunk of the food material (cat food tuna, canned mackerel, etc) and returns it to the colony to feed it to the carnivorous larvae.
In this process both larvae and foraging adult wasps are killed. This can be done without any risk to non-targeted insects or any other organisms, and I suppose we could label it a very “green” approach to yellowjacket control. It targets only these nuisance scavenger yellowjackets, and will not be effective on other paper wasps or bees, and also will not be effective on bald faced hornets. You can enhance the attraction to the station by placing a couple of drops of yellowjacket Attractant on top of the station, and this attractant is that same material sold for YJ traps, called heptyl butyrate, also available from Univar.
Mr. Pest Control