TULSA, Okla.

Since Oklahoma's crackdown on illegal immigration took effect on Nov. 1, enrollment numbers for Hispanic students in many Tulsa-area school systems have dropped.

School officials said the trend is most noticeable in the Tulsa Public Schools system, which has seen a drop in enrollment of 257 Hispanic students from the fall 2007 and spring 2008 semesters. There now are 7,764 Hispanic students enrolled in the system.

Gary Lytal, the school system's assistant to the superintendent for accountability and research, said that during the 2006-07 school year, Hispanic enrollment rose during the same October-to-January period.

The immigration measure, House Bill 1804, was passed by the Legislature last year and was signed into law by Gov. Brad Henry.

Among other things, it bars undocumentedl immigrants from receiving tax-supported services, requires employers to verify the immigration status of their employees and exposes employers to legal action for hiring unauthorized immigrants in place of U.S. citizens.

A principal at one Tulsa school that has lost Hispanic students said officials have no way to determine which students left the school because of enrollment boundary changes within the system or because of the new law.

"At the beginning of the year, we investigated to find out where all of our no-shows were," said Scott Griffith, the principal at Kerr Elementary School in southeast Tulsa. "We even drove to some of the homes and talked to landlords or neighbors. There were some students who had gone to Mexico, Nebraska or Texas, but we always have that mobility in our Hispanic student population."

A spokeswoman for Union Public Schools in Tulsa said spring enrollment figures for the system were not yet available, but Karen Vance, the principal at the district's Rosa Parks Elementary School estimated about 15 families have moved specifically because of the new law. The school’s Hispanic enrollment is about 35 percent, she said.