If you're into the GTA IV 100% thingy, you'll have to whack a lot of fly­ing rats. There are guides to show you the lo­ca­tions, but some rats are in tricky places to get to. But it wouldn't be Lib­er­ty City if you couldn't get your hands on an An­ni­hi­la­tor. Just get one, fly to a lo­ca­tion and keep fir­ing in the gen­er­al di­rec­tion of the pi­geon un­til there is one fly­ing rat less left. This ap­proach saves you walk­ing up and down a lot of stairs and try­ing to loose 4-star want­ed lev­els, and you get to lis­ten to your fa­vorite ra­dio sta­tion while do­ing it. Hap­py hunt­ing!