When visiting Cape Egmont, Taranaki, last week I came across a lovely group of about 20 of them, along the coastline, enjoying the last sun's rays of the day. They were still somewhat active, but when they landed on the grass stalks they remained still for enough time for me to get reasonable photos. The flight pattern of the Common Blue is very zig-zaggy and flicky, so it's not easy to get a shot unless they're still. The pristine condition of this group was heartening.
The New Zealand Common Blue is a small butterfly up to 23mm wingspan. It has an erratic fluttering flight and usually flies closer to the ground to be near a food source.
They lay single eggs which hatch in a matter of days. The eggs are laid on leaves, stems, flower buds and young pods of food plants, chiefly legumes of the Fabaceae family such as clover, Birdsfoot Trefoil and various native species. Newly hatched larvae eat small holes from young leaves or flower buds, and later feed mainly inside flowers.