The California gnatcatcher is a four-inch blue-gray bird weighing less than an ounce - but it's in the middle of a heavyweight battle over whether it should remain federally protected.
A San Diego County resident and other parties filed a lawsuit Thursday in San Diego, which claims the tiny bird's nesting grounds extend well into Mexico where it's not in decline.
San Diego-area resident Lou Marsh and two groups are challenging the U.S. Fish and Wildlife Service's designation of the gnatcatcher as a threatened species.
Marsh lives in an unincorporated area of San Diego County.
She said she can't develop her four-acre property because two gnatcatchers were found nesting on her lot.
Jane Hendron with the Fish and Wildlife Service said lawsuits have challenged the gnatcather since the 1990s.
"We were originally sued because we did not designate critical habitat at the time it was listed," said Hendron. "We made an initial critical habitat designation which was also subsequently challenged."
Hendron said the end result in 2003 was the setting aside of nearly 200,000 acres of public and private land in Southern California as critical habitat for the gnatcatcher.
The Pacific Legal Foundation is representing the plaintiffs and said the scientific designation is "flimsy," while costing property owners and businesses money.
The California gnatcatcher was put on the Endangered Species List in the early 1990s when findings showed the birds' habitat was under threat from urban sprawl in Los Angeles, Orange, Riverside, San Bernardino and San Diego counties.
Building within the designated areas requires special permits and may be prohibited unless there are mitigating measures implemented to accommodate the birds.
City News Service contributed to this report.
