Construction on a six-mile stretch of a steel and concrete wall along the Texas-Mexico border is expected to begin at the end of this month. But conservationists are urgently battling the government in court before it's too late for the National Butterfly Center, a private piece of property owned by the North American Butterfly Association (NABA) that could see a wall slice through its grounds.

The 17-year-old center sits on 100 acres just south of Mission, Texas, a city with the Rio Grande River at its back and an hour north of the state's southern tip.

Before it was purchased by NABA, the butterfly center's land was an onion farm, says Executive Director Marianna Treviño-Wright. And in the years since, the