We have had 3 european hornets in our house over the last 5 years. All were on the upper floor of the house. One was found dead; the other two were weak, flying close to the floor, landing frequently. Does this mean there is a nest close by? do they return to or re-use a nest year to year? Of course we are concerned that there might be a nest in the attic or wall of the house. This year for the first time we noticed many hornets around our fig tree in late August. Would this make it more likely that they nest near that tree next year? Thanks for your help.
European hornets don't reuse their nests from year to year, nor will their interest in your fig determine where they will nest. They will die with the cold.
Their nests are not easy to find, and though they can end up in attics or wall voids, we think you would have likely heard or seen more than 3 in five years. They are attracted to lights and may have flown in when a door or window was opened.
That said, you could always have a professional take a look. We would not recommend treating unless it were in your home.
Here is our page on them: https://www.extension.umd.edu/hgic/topics/european-hornets
Sounds good. Thank you.
You are welcome.