An abundance of clouded sulphur butterflies will be fluttering about Calgary this month, but it won't last long.

"Enjoy it while you can," said Tonya Mousseau, entomologist and biology professor at Mount Royal University.

It appears there are more the usual numbers of the pale to bright yellow coloured arthropods, due to healthy food supply for caterpillars in the Calgary region.

"If the caterpillars have a lot of things they can munch on; they're usually eating on leafy things, clover [and] alfalfa, then you see an abundance of the adults coming up as well," said Mousseau.

The butterflies develop first as an egg, which then hatches into a caterpillar that eats all it can until it pupates into a chrysalis from which the butterfly emerges.

But backyard bug watchers will need to act quick if they want to have a look; the average life span of most species of butterflies is two weeks to one month.

Mousseau said the flights of butterflies flapping around Calgary could be due to the health of pollinating flowers that support nectar feeding organisms.