I see you are in Vancouver therefore I would bet that the grubs that are infesting your lawn are European Chafer Beetle larva, they are an invasive species. Racoons, crows and skunks tear up the lawn to get at the larval instars that are feeding on the grass roots, as well as as when the larvae feed they create tunnels and voids in the soil and kill the grass plants. Due to the fact most municipalities have adopted cosmetic pesticide bans that prevent the use of insceticides to treat this foriegn pest you are kind of pooched as the animals are the secondary issue with the grub being the primary problem. Nematodes (specifically,Heterorhabditis bacteriophora) can be used that can be purchased from garden stores and they will help control the possibility of an infestation but the window for this has past and needs to be done in late July when the larvae are susceptible to this alternative. You can trap and shoot and whatever but they will just keep coming...they are like gummy bears for a 10 year old...
Keep as healthy a lawn as possible to help avoid the chafer from getting a foothold...alternatively, municipalities may be able to tell you what you can and can't do to your property but they don't generally prohibit retailers from still carrying certain chemicals that will do the job...The inscecticide by the trade name of Sevin will do the trick...you just need to find it...
