This is a public service message from NWBR.
There are millions of dogs who love dog parks and enjoy them safely every day. But please remember to keep an eye on your fosters and resident dogs. If you see them munching on something, take a quick second to check it out. It's probably an extra tasty poop, BUT it could be much worse.
If you see something suspicious, call the police! Alert the other pet owners who are there as well. If you discover your dog has eaten rat poison, induce vomiting (a few cc's of hydrogen peroxide squirted down the throat usually does the trick) and go straight to the vet. Time is important here, so this is not something you should wait out.
Pictured are some images of rat poison so you know what to look for.