The Lesser Black-backed Gull (Larus fuscus) colony at Keflavik International Airport has grown from around 1,000 pairs in 1975 to over 20,000 pairs in the early 1990s and to around 30,000 pairs in 2000. The colony is considered a serious hazard to both military and civil air traffic. The population of arctic foxes (Alopex lagopus), the only predator in Iceland capable of preying on these gulls, was very small in this area from the late 1950s until the mid-1980s. A decade ago we noted that the location of the colony had shifted away from an arctic fox breeding den near the airport. As there were no natural arctic fox breeding dens at the location of the gull colony and as the geography was not suitable for such dens, we constructed an artificial den there in autumn 2000 to attract arctic foxes to breed there. The design of the den was based on that of a natural arctic fox den excavated elsewhere. Between January and April 2001, bird carcasses were placed at the artificial den on a regular basis to attract the foxes’ attention to the den. Tracks in snow showed that foxes visited the den and removed the gull carcasses. Two vixens, one pregnant and the other lactating, were killed in the vicinity of the den in May and June 2001, respectively, and it was not used as a breeding den that year. We propose that arctic foxes should be totally protected in the area in order to test (a) whether wild arctic foxes are prepared to use an artificial den for rearing their pups, and (b) whether the occupation of a strategically placed den will result in a relocation of the gull colony to an area where aviation hazards are not a problem