As the song goes; ‘If you go into the woods today, you’re sure of a big surprise,’ and that is just what happened recently to two volunteers checking Timms trap lines in Aongatete forest. In a sunny glade, Barbara and Jenny saw a Forest ringlet, or Helms butterfly. It had alighted on the leaf of a grassy plant but, as they fumbled excitedly for a camera, it flitted away. The grassy plant was a sedge called Gahnia which is the food plant for the butterflies’ caterpillars. Sure enough, when they looked closely at the leaf blade where the butterfly had rested, there was a tiny green egg.
Forest ringlet butterflies are very rare so Barbara was excited to lead local entomologist Dr Peter Maddison to see the egg. But it was gone! ‘Darn robins!’ said Peter. Barbara was downcast but Peter pointed out that there will be more eggs, which restored her spirits.
Forest ringlet butterflies are unique to New Zealand. They used to be common but they are now so rare they are in danger of extinction. It seems likely that the extra predation by introduced rats, mice and maybe wasps is to blame, so the butterflies may be another native species that is benefiting from the rodent control at Aongatete.