Attendance took a hit in some areas of the Philadelphia School District this morning as the SEPTA strike entered its second day.

The system had no preliminary districtwide numbers as of this morning, but several magnet high schools which draw students from around the city reported that they had many fewer students than usual.

A handful of the schools, which usually have well over 90 percent attendance, reported this morning between 51 percent and 84 percent rates.

The district was expecting its 18 secondary magnet schools to be especially hard hit by the strike. Many of those students use SEPTA to cross the city. A transit strike four years ago caused a 25 percent absenteeism rate in the magnets on the first day.

Today, many students arrived at their schools exceptionally early, dropped off by parents who needed to get to work themselves. And parents inquired about picking their children up later if necessary, as rush hour traffic could be particularly bad.

"We had a lot of kids getting here at 6:30 a.m. to make sure they had a full day of school," said Ann Gardiner, principal of Bodine High School for International Affairs, 1101 N. 4th St. Attendance there was 73 percent.

Principals said their staff will use blogs and other forms of electronic communication to stay in contact with students who can't make it to school.

"We have set up a blog for students who cannot make it to check in for their teachers' assignments," said Thomas Davidson, principal of Constitution High School, 18 S. 7th St., where 63 percent of the students showed.

At Saul High School for Agricultural Sciences, 7100 Henry Ave., teachers signed up for a special free web service to communicate with students, said Principal Wendy Shapiro. Just under 70 percent of Saul students made it to school today.

The Franklin Learning Center, 616 N. 15th. St., saw just over half of its students report for class.

"I expect it will probably improve if there is a protracted strike as people find ways of coming to the school," said Principal Charles Staniskis.

In the meantime, all students have a set of textbooks at home so they should be able to keep up with their studies, he said.

Central High School, 1700 W. Olney Ave., reported 84 percent attendance as of 8:30 a.m.

"In past SEPTA strikes, it follows the same pattern. For the first couple days until people figure it out, we run five to 10 percent below what we normally run," said Principal Sheldon Pavel. "If the work stoppage lasts for more than a week, we end up stabilizing, at 2 to 3 percent below what we would normally run."

The school's cycling club is running a "valet" service for students who ride to school. The cycles are being parked in the dance gym, Pavel said.

"The kids have also done really well in setting up ride shares," Pavel said.

The Philadelphia School District's yellow bus service, which transports 37,153 district, charter and private school students, got a smooth start this morning, but officials expect delays and "gridlock" this afternoon, spokesman Fernando Gallard said.

The 161,500-student district provides bus service to students who must travel hazardous routes, are assigned to schools or participate in desegregation programs at schools a mile or two from their homes or have special education needs.

"We expect this afternoon that we are going to face some gridlock and there are going to be some delays, so we hope parents understand. We'll try our best to go as quickly as possible," Gallard said.

Gallard said the district expected to have preliminary districtwide attendance data later today. Teacher attendance is normal, he added.

School officials were taking the delays in stride, but hoping the crisis is short-lived.

"Certainly this will hold us up for a time. Children don't have a single minute to lose," said Gardiner, the Bodine principal.

Contact staff writer Susan Snyder at 215-854-4693 or ssnyder@phillynews.com