# The butterfly in your garden comes from Africa. It is the great-grandchild of the one that left

A butterfly with a 5–6 centimetre wingspan leaves Europe in autumn, crosses the Sahara and winters in the tropics. Its descendants return in spring. The circuit runs about 12,000 kilometres a year, flown by about six generations in relay. Follow them month by month.

By Marius Comper · 24 September 2026 · every number comes from a published study, linked under [sources](#surse)

## Twelve months, six generations, one circuit

Drag the slider and see where the butterflies are. The dot shows the approximate position of the population in each month, after the monthly maps of the model in Talavera et al. (2023).

### October–November: The great descent

The butterflies leaving Europe cross the Mediterranean and the Sahara and reach the Sahel savannah, where they start breeding. This is the longest leg in one butterfly's life: over 4,000 kilometres.

They fly by day, downwind, hundreds of metres up. Radar measured about 45 kilometres an hour in autumn.

### December–February: Winter in the tropics

As the savannah dries out, the offspring move south, to 5° north in West Africa and to the Equator in the east. From December to February the bulk of the population sits in the Afrotropics, not in the Maghreb.

The butterflies do not enter diapause: they keep moving and breeding all year, in up to ten generations where it never gets cold.

### February–April: The return

The offspring of the autumn arrivals cross the Sahara northwards and recolonise the Mediterranean shores. The proof came from hydrogen isotopes in the wings: many butterflies caught around the Mediterranean in spring had been born south of the Sahara.

The yearly circuit of the successive generations measures about 12,000 kilometres, crossing the Sahara twice.

### May–August: Europe and Romania

From the Mediterranean the wave moves north: local generations appear from May–June, and northern Europe is reached in late May and June. In Romania most records are from June.

From late August the butterflies head south again and breed once more on the way, in September–October.

Positions are approximate, after the monthly maps of the model in Talavera et al. (2023). The dot shows where the bulk of the population sits in each month. For scale: Bucharest to the Sahel is about 3,700 kilometres as the crow flies.

One caveat: the routes above were measured on the western circuit. Other populations circulate in Eastern Europe and Asia and meet this one, and how much they mix is unknown. Some butterflies reach Europe from the Middle East and Central Asia too.

## The traveller crossing the Sahara is 5–6 centimetres

The painted lady (*Vanessa cardui*) is orange with black and white above, marbled brown below. The drawing below shows it life-size, next to a ruler.

The wingspan, the distance between the wingtips, is 50–56 mm in the British guide and 55–60 mm in the Czech identification key. The drawing uses 55 mm, the middle of the European values.

A female lays about 500 eggs, singly on the host plant. In Britain and Ireland, the caterpillars prefer thistles; they also eat mallow, nettle and a few other plants. Egg to butterfly takes 33–44 days in warmth and over 60 days in the cold. The species lives on every continent except Antarctica and Australia.

How long an adult lives in the wild has never been measured. In the laboratory adults live about 10–24 days. The 12,000-kilometre circuit is about 218 million times longer than the butterfly itself.

## Two questions before you read on

Pick an answer for each. The page will not show the explanation until you commit.

### How much of the circuit does a single butterfly fly?

- The whole circuit, nearly 12,000 kilometres
- One part: a little more than 4,000 kilometres
- Only a few hundred kilometres

The longest leg known in butterflies is over 4,000 kilometres: from Europe to the tropical savannah, across the Mediterranean and the Sahara. The rest of the circuit, up to 12,000 kilometres, is flown by the generations that follow.

About six generations succeed each other in a year. Each flies one leg and lays its eggs; the offspring continue the journey. About three generations separate the butterfly that left for Africa in autumn from the one in your garden: hence the great-grandchild.

### Where do the butterflies that left Europe spend the winter?

- In North Africa, in the Maghreb
- South of the Sahara, in the tropics
- They all die in autumn

From December to February the bulk of the population sits in the Afrotropics, not in the Maghreb. Some reach the Equator. They breed there, and their offspring head north in spring.

Painted ladies have no dormant state: they keep moving and breeding all year, in up to ten generations a year where it never gets cold.

## The 4,200 kilometres that should not have been possible

One October morning in 2013, painted ladies turned up on a beach in French Guiana. The species had no stable populations in South America.

- How far it could flap without wind and without rest: 780 km

- How far with wind, but flapping all the way: 1,900 km

- How far they flew, with wind and gliding: 4,200 km

The first two bars are what the energy models say; the third is the minimum distance reconstructed from the winds. Source: Suchan et al. (2024).

Three of the ten or so butterflies were caught alive at around 6 in the morning on 28 October 2013. Analyses of winds, genes, pollen and isotopes showed they had crossed the Atlantic from West Africa: at least 4,200 kilometres in 5–8 days. The isotopes suggested some were born in Western Europe, which stretches the whole journey past 7,000 kilometres.

Without wind they would never have made it: on its fat reserves a butterfly can flap for 780 kilometres at most. Even with wind they would have failed had they flapped all the way: that ends around 1,900 kilometres. In 2013, the butterflies alternated flapping with gliding, like monarch butterflies: about 15% flapping and 85% gliding.

It is one of the longest flights ever documented in individual insects.

## When the butterflies reach Romania

The GBIF database holds 961 *Vanessa cardui* records from Romania. Here are the months they were seen in.

January: 0, February: 0, March: 1, April: 22, May: 185, June: 326, July: 188, August: 124, September: 68, October: 28, November: 4, December: 0

15 of the 961 records carry no month and are not in the chart. Last checked: 23 September 2026.

The wave arrives in April–May and peaks in June: 326 records, about one in three. The last vanish during October–November.

Most records are from 2026, the current year (186), and from 2019 (172). The years 2009 and 2020 show no Romanian records at all: a sign of how little was recorded then, not of missing butterflies.

The records come mostly from people photographing nature (iNaturalist, Observation.org) and from a museum database (ZOBODAT). So the chart also shows where people look, not only where butterflies fly.

## True or false?

Eight statements about the butterfly. Some sound like stories and are true.

- **A single butterfly flies the whole 12,000-kilometre circuit.** False. About six generations fly it in relay. The longest leg known for one butterfly is over 4,000 kilometres. ([Talavera et al. 2018, Biology Letters](https://doi.org/10.1098/rsbl.2018.0274))

- **Every year the butterflies cross the Sahara twice.** True. South in autumn, north in spring. The desert is 1,500 to 2,000 kilometres wide. ([Talavera et al. 2018, Biology Letters](https://doi.org/10.1098/rsbl.2018.0274))

- **In winter, most of Europe's butterflies sit south of the Sahara.** True. From December to February the bulk of the population breeds in the Afrotropics, not in the Maghreb. ([Talavera et al. 2018, Biology Letters](https://doi.org/10.1098/rsbl.2018.0274))

- **Some painted ladies have crossed the Atlantic to South America.** True. In October 2013 a few reached a beach in French Guiana after a wind-assisted flight of at least 4,200 kilometres. ([Suchan et al. 2024, Nature Communications](https://doi.org/10.1038/s41467-024-49079-2))

- **With a tailwind they fly at over 40 kilometres an hour.** True. Radar measured about 50 km/h in spring and 45 in autumn, at heights up to over 1,000 metres. ([Stefanescu et al. 2013, Ecography](https://doi.org/10.1111/j.1600-0587.2012.07738.x))

- **A female lays about 500 eggs.** True. The eggs sit singly on the host plant, and adults can breed within days of emerging. ([Animal Diversity Web](https://animaldiversity.org/accounts/Vanessa_cardui/))

- **In Romania they arrive from April–May and peak in June.** True. Of 961 Romanian records, 326 are from June: about one in three. The data comes from people, so it also shows where people looked. ([GBIF, 23 September 2026](https://www.gbif.org/species/4299368))

- **They spend the winter dormant, waiting for spring.** False. They never enter diapause: they keep moving and breeding all year, in up to ten generations where it never gets cold. ([Talavera et al. 2023, PNAS](https://doi.org/10.1073/pnas.2218280120))

## How we know all this

Distances and dates come from published studies, read in full; the list says what each one was used for. Where sources give different values, the range is printed: the 12,000–15,000 km circuit, the 1,500–2,000 km Sahara, the 50–60 mm wingspan.

Two things are missing because they were never measured anywhere: how long an adult lives in the wild, and exactly which way the butterflies of Eastern Europe travel. The page says so plainly next to each.

- Stefanescu, C. et al. (2013). Multi-generational long-distance migration of insects: studying the painted lady butterfly in the Western Palaearctic. Ecography 36(4). https://doi.org/10.1111/j.1600-0587.2012.07738.x — six generations, the circuit of up to 15,000 km, the radar-measured speeds and heights (accepted manuscript read)
- Stefanescu, Soto, Talavera, Vila, Hobson (2016). Long-distance autumn migration across the Sahara by painted lady butterflies. Biology Letters 12: 20160561. https://doi.org/10.1098/rsbl.2016.0561 — the flights of over 4,000 km from Europe to the savannah, proven with isotopes
- Talavera, Bataille, Benyamini, Gascoigne-Pees, Vila (2018). Round-trip across the Sahara. Biology Letters 14: 20180274. https://doi.org/10.1098/rsbl.2018.0274 — the spring return, the circuit of about 12,000 km, winter in the Afrotropics
- Talavera et al. (2023). The Afrotropical breeding grounds of the Palearctic-African migratory painted lady butterflies. PNAS 120(16). https://doi.org/10.1073/pnas.2218280120 — the tropical breeding grounds, the monthly maps behind the map here
- Suchan et al. (2024). A trans-oceanic flight of over 4,200 km by painted lady butterflies. Nature Communications 15: 5205. https://doi.org/10.1038/s41467-024-49079-2 — the Atlantic crossing, in 5–8 days, on wind and gliding
- Myers et al. Vanessa cardui. Animal Diversity Web, University of Michigan. https://animaldiversity.org/accounts/Vanessa_cardui/ — eggs, development, host plants, the migration calendar
- Butterfly Conservation. Painted Lady. https://butterfly-conservation.org/butterflies/painted-lady — the 50–56 mm wingspan, thistles as the preferred plant
- Beneš, Dvořák. Vanessa cardui, identification key card. lepidoptera.cz. https://www.lepidoptera.cz/urcovaci-klic/cardui.pdf — the 55–60 mm wingspan
- Catalogue of Life, via GBIF: the Romanian name Fluturele de scaieți. https://www.gbif.org/species/4299368 — the species' Romanian name
- GBIF, Vanessa cardui records from Romania, accessed 23 September 2026. https://www.gbif.org/species/4299368 — 961 records: months, years, sources