TOPEKA, Kan. (AP) — Topeka Zoo staffers are preparing for the birth of two or three Sumatran tiger cubs as early as this week, and their plan includes time indoors and late-night checks for the mother.

The Topeka Capital-Journal reports that starting Wednesday, staff will bring pregnant tiger Jingga inside at noon, in case she goes into labor during the day. The zoo expects the routine to continue until Jingga’s labor starts.

Her due date is May 1.

Animal care supervisor Shanna Simpson said tigers typically give birth at night, when it is quiet and safe. Staff members will start this week to check between 10 p.m. and 2 a.m. for signs of labor.

The zoo sees the births as important because only about 500 Sumatran tigers are left in the wild.