In my experience, most dog owners are like the user who started this thread. They do what they want, having their dog constantly off leash in areas where it's clearly not allowed, and then rationalize it to themselves with something like "well my dog's well behaved and would never hurt a fly!" It's incredibly inconsiderate to both the environment (dogs are constantly chasing and damaging wildlife, a lot of poop gets left behind as the owner is walking off in front and doesn't notice) and other people (many people don't like dogs, dogs are dangerous for bicyclists and small kids, and some people have smaller dogs who they don't want strange dogs interacting with), and indeed the badly behaved dog owner will see signs of this on a daily basis, but chooses to consciously ignore all of them by pretending none of it's happening.
Dog culture around the Bay Area where I am has reached peak absurd. With more dogs in SF now than kids, people treat their dogs like they would human children. Off leash dogs in on leash or even no dog areas is the norm. At least a few times a week I'll see an off leash dog to something bad to a person or another dog, and the owner pretend-chastise them with a, "ooohhhhh Fido, silly dog, don't do that" (but in a sweet tone so the dog is not actually being chastised) followed by a "he doesn't normally do that". You know of course that Fido does normally do that on a consistent basis, and the owner is pretending Fido doesn't because they really don't care.
It's frustrating to me, and probably frustrating to other people on here too. There's no real enforcement anywhere, so the only thing we can do is ask dog owners to put their animals back on leash, which will be ignored. It's like fighting entropy at this point, and if you're anything like me, you sort of wish nebulously that people would just be better.
In cities that have a lot of people from all over the country and world you end up with a lot of culture clashes. People do things that in the context they grew up in are totally reasonable and normal, but from someone else’s perspective seems uncomfortable or even dangerous.
In theory municipal rules should harmonize, albeit with some people left unhappy, but it’s another American cultural quirk that some rules are widely ignored. But which ones is again a matter of geographic diversity.
All the responses in this thread have been cordial and relevant, so it is disappointing to see some of them met with this kind of silent disapproval, which is reserved for non-sequitors, those acting in bad faith, or impolite speech.
I must say that in this sort of situation - an area near a nesting site - I absolutely agree a dog shouldn't be free to run around. But I imagine there are signs specifically warning people against doing that. There are areas here where I have to do the same, for example near areas where people hunt deer (a lot nearby) or where there are bears (only seen warnings in Slovakia). But outside of those areas, with an conscientious owner and an attentive, trained dog who listens to their owner - there's no reason not to unless it's someone who hasn't bothered training their dog.