VW Sweden and DDB Stockholm have come up with another clever idea for a "Winter-Adjusted offer" (after its 2011 stunt in which an offer was only valid once the ice melted in a field where the billboard was located).

This year, to advertise its Skiteam cars (which include four wheel drive and a roof box for skis), the brand is live-tracking one osprey bird on its winter migration, following its path down to Africa and back again, using GPS. The experiment is being done in partnership with the University of Lund. The offer is only valid until the bird returns north after the harsh Swedish winter (it's currently in Germany). TV spots, print ads, banner ads and outdoor drive visitors to the campaign site, where visitors can see the bird's progress on a map, learn more about the offer and guess the return-date of the bird to win prizes. To update people on its journey, VW also sent tweets and posted Instagram shots from the bird's account.