Relocating nests of social wasps

Several years back, while surfing some great sites on social wasps, I found references to techniques of relocating nests which are built in locations where they may be a threat to people. This enables the wasps to continue living out of harmís way, and at the same time, eliminates the threat they may pose to people in the vicinity. This is especially commonly done in Germany, where the hornet Vespa crabro is protected by law! It is illegal to kill hornets, and pest control operators and even fire departments are trained to relocate problem nests.

Unfortunately, with the exception of experimental techniques of using wasps for agricultural pest control, relocation is seldom practiced in Asia, especially in highly modern and urbanized cities like Hong Kong. Here, nests are usually demolished with a jet of insecticide. Every time I see a nest in one of the urban parks, I know it is only a matter of time before it is destroyed, even though sometimes the nest is 30 feet or more above ground, in a tall tree, and poses absolutely no danger.

I first started relocating nests in the spring of 2005. I went round many of Hong Kongís parks in an attempt to round up all nests built in risky locations and relocate them to a deserted area. I was quite successful with this, although I was stung several times. Towards the end of spring, I perfected the technique for moving nests of paper wasps (Polistes and Parapolybia). I had limited experience in doing so with hornet nests during that year. However, starting from 2007, I had more experience with hornets, even relocating some of their nests to my apartment. In this section, I describe methods of relocation over the past couple of years, and I will update whenever I have the time.

Please note that the info here is provided for reference only; it is not recommended to attempt nest relocation without sound experience and knowledge of wasp behaviour. If you are unsure or inexperienced with regards to such techniques, or if there is a chance you might be allergic to wasp venom, never attempt this!

Wasp colonies are easy to deal with early in Spring, where there are few or no workers. It is even easier if there is only the queen, and workers havenít hatched. However, the chance of survival in this case is lower, because the queen sometimes gets lost after moving to the new location, or may meet danger outside.

Firstly, it is important to understand the defensive nature of such wasps. Unlike honeybees, hornets or yellowjackets, which usually swarm out and attack any moving thing upon provocation, paper wasps usually direct their attention solely towards the intruder that disturbed the nest, and are thus easier to capture without getting stung. There are two ways in which the wasps attack in defense of their nests and attack. If the nest area is persistently vibrated or disturbed, the wasps may fly out and pursue the intruder. In such cases, usually only one or two stings are delivered, although some more defensive species may latch on and sting many times. However, if the nest is brushed into, the wasps usually latch on to the offending object and sting it repeatedly. Hornets, on the other hand, will circle the area aggressively once the nest is disturbed and attack any moving object nearby. Even with a small colony, it is essential to carefully capture the workers one by one. Relocation of a large hornet colony is not advisable without a protective suit.

The method I used most frequently earlier was to capture the queen and any workers present, transfer them to a transparent plastic bag and then remove the nest separately. There are several advantages to doing so. The most obvious reason being that with no wasps on the nest, the nest can be removed intact with care and without fear of being stung! I always prefer to remove as much of the nest as possible, with the pedicel (the "stem" attaching the nest to the surface it is built on) intact. It is always easier to do this with bare hands. After this, I chill the wasps to the point of inactivity, usually with a portable icepack. This is to make sure they do not fly away immediately upon being let out of the holding bag. There are two major problems with this; firstly, the timing must be just right. If chilled too little, the wasps will often fly away upon reintroduction to the nest. And of course, if chilled too much, it could be fatal to them. Also, the wasps usually do not become inactive at the same time; some may be still actively struggling while others are almost dead during the same period of being placed on ice. I have found that the important individual is the queen; it is important to get her chilled just nicely and introduce her back to the nest along with at least 2 of the workers (if present). The nest is then placed in the new location, and the wasps introduced back.

I have also relocated nests (usually fixed just outside my window) with the wasps still on the nest, after being kept indoors for a couple of days. More on this will be covered later. Please follow the links below for more info and accounts of my experiences (both successes and failures) in relocating nests.

Relocations carried out in 2005
Relocations carried out in 2006