Just passin’ thru

Some butterfly species are known for their long annual migrations. Each year the Monarch Butterfly (Danaus plexippus) makes a 3000km long flight from Canada to Mexico. The Painted Lady butterfly undertakes an even longer 9000km journey from Europe to Africa every year. This trip spans several generations. Australian butterflies such as the Meadow Argus, the Australian Painted Lady and the Caper White are known for their annual treks spanning thousands of kilometres.

The Caper White butterfly (Belenois java) (male is pictured above and below) is a primarily white butterfly that is often mistaken for the Cabbage White (Pieris rapae), pictured right. It is distinguished from the latter by having black wing margins and veining and orange marks that can easily be seen when the butterfly is at rest with its wings closed. The butterfly is named for the Caper bushes (Capparis sp.) that it lays its eggs on.

Caper Whites have several migration routes within Australia. The one that brings these butterflies our way starts each Spring when they leave their breeding grounds in the northern Flinders Ranges and head south. Their trek covers several thousand kilometres but how far they actually travel and in which direction depends on the weather, particularly the prevailing winds. A couple of times a decade very large populations of Caper Whites migrate together.

This year there seems to be a higher than normal number of Caper Whites in the district. Mass migration or tail winds? We’ll have to see.