Sparvar is swedish for sparrows, a plump brown-grey bird with short tails and stubby, powerful beaks. Now, why would anyone name a tracker after a bird. Usually tracker names include cool words such as torrent, scene, leech or if it is a swedish tracker in most cases the prefix swe.
It goes back to the court proceedings against The Pirate Bay. Monique Wadsted, one of the prosecutors and representing the american film companies in The Pirate Bay trial, became infamous for her 'fried sparrows' analogy of file sharing in her final statement, on the last day of the trial:
(translated from swedish, translation stolen from a blogg on the net)
To consume movies and TV shows through The Pirate Bay is like lying on your back and let fried sparrows fly into your mouth, regardless of whether or not you’re hungry. The sparrows are also piled up around you so you can consume them whenever you want, requiring no effort on your part.
And, to cut a long story short, the tracker was named Sparrows, or Sparvar in swedish.
Also, the user classes have been named to fit the sparrow theme. When you join sparvar.org you are a sparrow baby. Banned users are fried sparrows and staff are ornithologists.