Where do the white butterflies come from? Where do the white butterflies go?
Every year in South Africa, during December-January, little white butterflies take to the air in their thousands, all flying in the same direction. They visit gardens and flowers along the way. Even though it is a yearly occurrence, many people don’t know why it happens.
This is the migratory flight of the Brown Veined White Butterfly, Belenois aurota (AKA Pioneer white, African Caper White and in Afrikaans: Grasveldwitjie). They belong to the Pieridae (the ‘Whites’) family of butterflies and migrate north-east over the interior of South Africa.
During good rainy seasons, the butterflies’ population is bolstered by the abundance of leaves for caterpillars on host plants (Capparaceae: specific genera include; Boscia, Shepard’s trees; Maerua, endemic trees of Mozambique and Capparis, Caper shrubs). These caterpillars subsequently metamorphose into butterflies.
The adults mate and lay eggs on the host species (they breed before they fly). Afterwards they begin their migration. They fly and continue to fly until they succumb to complete exhaustion. If they get sufficient food along the way, making pit stops in gardens, they can fly as far out to the Mozambique Channel and perish in the Indian Ocean.
After a few years of migrating eastwards they will turn around and migrate back again. So the cycle continues and white butterflies take to the sky. I will update this post as soon as the first of the whites appear this year.
Little White Butterfly (LWB) Migratory Observations since Dec/Jan of 2013/14
- 2013/14: Arrived on 08 Jan 2014. Masses on 11 Jan 2014. The chickens try their best to catch some who flutter to close to the ground, but to no avail – very amusing to watch them race after the little whites. LWB reach Pretoria on the 12th of Jan. Butterfly run ends on 14th of Jan.
- 2014/15: Butterflies are early on the 27th of November 2014. Smaller LWB run than previous year, ended on the 29th.
- 2015/16: LWB run on the 9th of January 2016 and apparently a later one in March in Bloemfontein.
- 2016/17: Very small LWB run this year and arrived late on the 3rd of February 2017.
- 2017/18: No LWB run… Maybe it is their turn-around year?
- 2018/19: Butterflies are back on 05 Feb 2019! Was getting a bit worried there… 😉 Drips-and-drabs throughout Feb and Mar.
- 2019/20: Due to the amazing amounts of rain we have received the butterflies were back in their thousands with a absolutely spectacular migration starting late January and ending early February with smaller migrations earlier in Jan and later in February. Social media was flooded with photos!
- 2020/21: There have been a few early fliers around the 13th and then again on the 26th of December. Perhaps they’ll pitch again in their thousands for the late Jan show?
Showcase from the 2020 Mass Migrations
Update 2020: What about all the little white butterflies in fall?
Those are the common dotted border butterflies, Mylothris agathina, who are abundant in March, April and May. They also belong to the same family of butterflies, but are a different species. You would notice that they have a single orange spot on their fore wings (some may have completely orange wings) and they have a single ‘border’ of spots on the ends of their wings (no brown veins).