Painted ladies check into Malta before Arctic adventure

If you have noticed more butterflies than usual lately, you are not imagining it.

Thousands of painted ladies are passing over Malta on their way north, driven by warmer temperatures and dwindling vegetation in North Africa. 

Enjoy the spectacle while it lasts. The butterflies are only passing through. Destination: Northern Europe and as far as the Arctic Circle.

The heavy passage of butterflies over Malta started about four days ago, with painted ladies (Vanessa cardui) travelling from North and Northwest Africa as well as from the fringes of the Sahara Desert, across the Mediterranean onto the European mainland, explained Prof Louis F Cassar from the Institute of Earth Systems at the University of Malta. 

Like birds, butterflies tend to undertake journeys across seas and oceans, usually in spring and autumn in the case of the central Mediterranean area. 

This happens for environmental reasons, including rising seasonal temperatures in sub-Saharan and Northern Africa, and the decline of flora for nectar for the adults and host plants for larvae. Butterflies seek habitats with these two assets that are crucial to their survival, Cassar explained.

Although the phenomenon is described as migration, Cassar said this was not the correct biological term because the same individual did not manage the entire journey.

“It is known as multi-generational passage,” he specified. Unlike birds, it is not the same individual butterfly departing the North African coastline that will eventually reach Northern Europe. 

“This butterfly species tends to live for only a few weeks. It will, therefore, take several generations to arrive in Scandinavia and, likewise, numerous other generations when the species flies back to North Africa in autumn,” said Cassar, whose academic interests are biodiversity conservation, island biogeography and entomology.

Occurring most years, the numbers vary greatly, from a few scores to millions, as is the case this year – “truly a sight to behold!”

It is not just in gardens that eye-catching flutters of butterflies are being seen; they have even been noted hovering around swimmers in the sea, as well as in urban areas.

‘One of the most beautiful natural spectacles’

The “exceptional” numbers observed this year are likely to be the result of favourable breeding conditions in North Africa and Southern Europe, combined with weather systems and winds that facilitated movement across the Mediterranean, according to pest controller Arnold Sciberras.

“When these factors align, Malta can experience some truly spectacular migratory events,” he said, describing the scene as “one of the most beautiful natural spectacles” currently unfolding across the Maltese islands.

The painted lady is one of the world’s greatest migratory insects, and populations travel thousands of kilometres, crossing deserts, seas and mountain ranges. 

“These migrations remind us that the archipelago is an important natural crossroads connecting Europe and Africa, serving as a temporary refuge and passage point for countless migratory organisms.

“The Maltese islands are an important stepping stone on this incredible journey through the Mediterranean,” Sciberras said.

While birds often received most of the attention, butterflies, dragonflies, and many other insects are also “undertaking extraordinary journeys above our heads”, he pointed out. 

“What makes this season remarkable is the sheer abundance of butterflies – in their thousands. From valleys and countryside tracks to coastal cliffs, gardens and urban areas, painted ladies have been present in numbers that are seldom witnessed,” he continued.

While the phenomenon occurs every year, particularly noticeable influxes are often recorded on a one- to two-year cycle. 

Lots of white butterflies

Another interesting feature of this year’s migration has been the abundance of white butterflies, particularly the small white (Pieris rapae). 

Although not as well known for migration, the small white is also capable of long-distance movement and is sometimes observed arriving alongside the migratory waves of painted ladies, he continued. 

This did not happen every year, making this season particularly noteworthy for butterfly enthusiasts and naturalists alike.

In rare circumstances, painted lady migrations may also be accompanied by other species, such as the small tortoiseshell (Aglais urticae) and the large tortoiseshell (Nymphalis polychloros).

Such events are uncommon and often generate considerable excitement among observers as they often involve species that are otherwise absent from the islands, Sciberras said.

The Maltese islands have also occasionally been visited by the magnificent plain tiger (Danaus chrysippus), another migratory butterfly known for its striking orange, black and white colouration. 

“Although far less frequent than the painted lady, sightings of the plain tiger are always welcomed and serve as a reminder of the incredible journeys that butterflies can undertake across continents and seas.”

For naturalists, photographers and anyone who appreciates wildlife, this year’s migration is likely to be remembered as “one of the most impressive butterfly movements” witnessed in recent years. 

“It is a rare opportunity to observe nature at its finest and to appreciate the resilience and determination of these delicate travellers,” Sciberras said.

“Take a moment to look closely at the flowers and vegetation around you. Chances are you will encounter one of these remarkable migrants resting, feeding, or continuing its long journey northwards.”