Upokongaro School pupils have been participating in a citizen science project organised by the Moths and Butterflies of New Zealand Trust.
All classes at the school located 10 kilometres north of Whanganui participated in the project by tagging and releasing butterflies.
Tagging the butterflies helps to monitor where they go during the winter months and where they fly to in spring.
If anyone sees a tagged butterfly, staff and students ask that you log into the trust's website to report your sighting.
"It's special to have Monarch butterflies in New Zealand," pupil Maile Browne said.
"It's our responsibility to look after them," Kayla Lloydd followed up.
"If we don't look after them, they could become extinct," Te Rangimarie Barber concluded.
The students have been learning about things such as needing to plant swan plants to see Monarch butterflies and protecting eggs and caterpillars from predators.
Butterflies can be tagged when their wings are dry and the tags do not hurt them.