The creation of an off-leash dog park in the center of Cesar Chavez Park is a disaster.

You wouldn't think so from the happy dogs and dog-owners romping through the grass. These people are delighted, and can't imagine what could be wrong with allowing their dogs to be leash-free outside the off-leash area during their walks to and from the center of the park, or through the marshlands near the marina. The entire park has become one big off-leash park to most of them and the wetlands and shoreline areas are now crawling with leash-free canines because, after all, they and their owners are on their way to the off-leash area, just came from the off-leash area, or point out that their dog isn't really bothering anyone.

I speak as a resident in the neighborhood who walks through the marshes and around the shoreline two or three times a week, and has seen a steady increase in the mutilated carcasses of rabbits, snakes, and birds, and a steady decline in the wildlife as a whole. It's a simple matter, really; where would you build your nest? Where would you stop to rest during a long flight along the California coastline? Most creatures, however simple, elect to avoid the sea of yapping canines that are now the primary wildlife at Cesar Chavez.

There are other good reasons to keep dogs on a leash. Some people are frightened of dogs, and dogs have no idea which people are and aren't afraid. One of my elderly clients suffered a broken bone when a dog dragging a leash behind it circled and tripped her. Dogs dart around on the bike path and cause a hazard to riders.

But I miss the birds. My favorite music is the sound in the marshes when the dogs are long gone and the birds begin their communicative games of flirtation, warning, and joy.

I know the dog owners did a remarkable job of crafting the off-leash park and organizing for its support, and I salute those who are responsible users of the off-leash area. But those who use the park responsibly need to work much harder to communicate to those who don't, or the off-leash area will be jeopardized along with the wildlife. The off-leash area is a great benefit to dog owners who try desperately to keep their dogs healthy and give their dogs a chance to run free outdoors. But dogs and wildlife are an impossible mix even for dogs which are beautifully trained, and all the creatures in the marshlands, even the snakes, play an important ecological role.