The U.S. Army Corps of Engineers at Lake Red Rock is looking for volunteers to tag Monarch butterflies.

Park Ranger Tracy Spry says the group will attempt to tag the butterflies as they pass through the Red Rock area during their fall migration. Two sessions will be held: the first on Friday at 4 p.m. in the South Tailwater Recreation Area, and again on Saturday at 10 a.m. in the same location.

Data from tagged butterflies may be used to help researchers track the monarchs’ journey to Mexico.