Western Meadowlarks build their nests on the ground, and they need a quiet meadow with thriving greenery for that purpose. You’d think that in the 90 acres of Cesar Chavez Park, finding such a place would be no problem. But where? In the southern half of the park, practically every square inch gets mowed, and mowers kill birds if they nest there. In the northern half, there are some slopes and meadows where the mowing machines don’t go. But there is a hard-core minority of dog owners who don’t respect nature and don’t observe leash laws. They feel privileged to let their animals run loose anywhere and everywhere in the park. Even the Protected Nature Area on the north side, with its signs barring dogs and people on penalty of fines, means nothing to this clique. They easily violate the partial boundary fence put up two years ago to separate the off-leash area from the nature area. The meadowlarks aren’t the only victims of the war against nature that irresponsible dog owners wage. Savannah Sparrows, also ground nesters, have come and gone this season without staying to breed, as they were able to do three years ago when part of the meadow near the Flare Station was allowed to develop. At the turn of the century, City Council granted dog owners 17 unfenced acres to run their animals off leash. That’s far more acreage than any canine needs for exercise. But it isn’t enough for the handful of irresponsible owners who claim the whole park, every park, and the whole city as their private dog toilet, exercise run, and hunting preserve. Most dog owners are responsible citizens and many love and appreciate nature. But the rabid element sets the tone, and neither Marina management nor the city’s animal control services lift a finger to stop them.