By Shivika Mala
Kaleidoscopes of monarch butterflies are brightening Auckland's winter skies and bringing joy to residents around Blockhouse Bay, Mt Albert and Onehunga.
Jacqui Knight, Monarch Butterfly New Zealand Trust trustee and secretary, said it was unusual to see the majestic insects breed during winter.
"Many people comment how they never used to see them breeding at this time of the year, and it looks like the behaviour of these stunning butterflies is changing. We have scientists reviewing the data to actually measure the change."
She added that during winter, depending on the region, monarch butterflies would not breed until spring.
Knight said the trust started getting sighting reports last week.
"Monarch butterflies usually overwinter in trees with oily or waxy leaves/needles. We believe they leave behind a pheromone so that they can come back to the same place and form large groups.
"There was something really magical about seeing large numbers of these beautiful orange and black butterflies clustering all together," she said.
She added that the butterflies being sighted were two to three months old and the weaker ones might not survive winter.
Apart from the Auckland sightings, the trust was aware of overwintering of butterflies in Napier, Christchurch and Nelson.
Knight urged people to report any sightings to the trust.
"Possibly there are other places too but we rely on local people to report them to our website. The trust is urging everyone to report sightings of monarchs (and other butterflies and moths, individuals or groups) into the website set up for the purpose-www.mb.org.nz."
The trust has been monitoring the monarch population in New Zealand for more than 10 years.
Knight said having monarch butterflies around was hugely educational for children as they inspired a sense of wonder and opened children's eyes to biodiversity in their own back yard.
"Monarch butterflies are an indicator species and if we study how they are changing we can reflect on how our environment is changing and adjust our behaviour to improve our environment.
"Just like the canaries in the coal mine a hundred years ago," she said.
Knight said the first sighting of butterflies overwintering in Onehunga and Blockhouse Bay was in 1984.