I am constantly looking out for them, wherever I go when it's sunny, and always have a camera in my pocket in case I find one to photograph.
I live in the far north of our country, meaning that Summer and warm temperatures hang around for a bit longer than the more southern areas of New Zealand. Consequently we see butterflies for more months of the year (lucky us).
A few facts:
Our Common Blue (Zizina otis labradus) is a small butterfly 17-27mm (and I've seen some even smaller). They are widely spread throughout New Zealand and it is suggested they were blown over from Australia in the 1800's.
They can be found in grassy areas where plants like Verbena, Birdsfoot Trefoil, Clover and Vetch are found. They also like sandy and gravelly areas (really difficult to spot them on gravel because of their greyish colouring).
They lay a single egg, that can hatch within days, on leaves, stems, flower buds and young pods of food plants of the legume Fabaceae family.
It seems to be one of the few New Zealand butterflies that does not have parasites, which is said could be due to its food plants naturally containing cyanide, or perhaps that no parasites have been noticed yet.
It is thought to overwinter at 3rd instar stage, at which time the larvae move to the shelter of the base of the food plant, in tall vegetation, and spend the colder months in diapause (a period of physiologically enforced dormancy between periods of activity) or quiescence (being at rest, quiet, still, inactive or motionless). These instar pupate in September/October, but if they run out of food they might pupate early (and will be smaller butterflies).
Ref: TERRAIN, NZ Landcare Research, NZ Butterfly Info