Other words of advice. Always have a can of pepper spray handy, as well as a spare plastic bag. Pepper spray is good for aggressive stray dogs and may also be good against wild animals in areas prone to rabies. And rarely, for the un-neutered, un-socialized, adult male dog brought to the dog park.
Coyotes are extremely dangerous to dogs. Even a strong pit bull (a “nanny dog”) can be badly savaged by one. Dogs think about fighting for dominance. Coyotes think about killing for food, territory, or to protect a litter. They think of dogs as food.
You can become everyone’s friend by getting expendable dust pans and cat litter scoops at the dollar store, and leaving them by the scumber waste can.
Cheap fly paper strips are also great. Fill a discarded drinking water bottle with tap water, and secure one end of the strip under the cap, to put on top of the scumber waste can when the flies are out in force.
If the dog park is prone to annoying small mud puddles, a big sack of generic kitty litter can be just the thing for less muddy dogs.
If you allow your dogs (as I do) out in the backyard, be thinking about coyotes that might lurk in the woods beyond and have a handgun or rifle nearby to grab and frighten the critters away if they attack your dogs.
Coyotes are in every county in the U.S., I've read.
Beware the pairs too. A large dog can usually stand one off. But where i walk they often work in twos. Lure the dog into the woods where a second coyote is waiting. Then tag team on the take-down.