Searching for Birthwort with the Spanish Festoon Butterfly

Searching for Birthwort with the Spanish Festoon Butterfly

Spanish Festoon (Photo: Steve Andrews)

The Spanish Festoon (Zerynthia rumina) is a very pretty butterfly in the Papilionidae or Swallowtail butterfly family. It has strikingly patterned wings of yellow, red and dark brown with zig-zag markings on its hindwings. It is found in Spain, Portugal, North Africa and southern France. I have seen the butterflies in scrubland and pine and oak forest near where I live, but until today I have never seen any of the Birthwort species (Aristolochia spp) this butterfly uses as food-plants for their caterpillars.

I have lived in Quinta do Conde in Portugal for the last five years but have never managed to find any type of Birthwort growing here so it has been a real mystery for me, as to how these butterflies survive here. Today after a lot of searching, I discovered a clump of Round-leaved Birthwort (A. rotunda) growing amongst trees and heather at the top of a bank.

Spanish Festoon habitat (Photo: Steve Andrews)

I had to climb up to find it, and this is why I had never seen it before, although I often walk through this part of the woodland. A female Spanish Festoon has to find this plant or other Birthwort species on which to lay her eggs. There are no other options. The distribution of the food-plants, as is the case with most butterflies and moths, is one of the main factors responsible for the distribution of these insects. In fact, if you find a colony of a particular butterfly or moth, you can be fairly certain that the plants the larvae of that specific species need will be growing nearby. 

Round-leaved Birthwort (Photo: Steve Andrews)

The Spanish Festoon is flying very early this year. Most sources say that it can be seen from April onward, although the excellent Collins Butterfly Guide, which says this butterfly flies from late March to May, also points out that it has been recorded in February. With the Climate Crisis making the weather a lot warmer, and leading to droughts and the very real danger of forest fires in Portugal, butterflies and other species of flora and fauna are directly affected by changes in the weather. 

The Birthwort species are poisonous plants that are dangerous for humans to consume, because poisoning from these plants can lead to kidney failure. These plants were once used to cause uterine contractions, hence the name “birthwort,” but their usage as a medicinal herb has mainly been abandoned due to the dangers of the toxins these plants contain. For the caterpillars of the Spanish Festoon, as is the case with the larvae of many butterflies that have poisonous food-plants, the poisons in the plant become a form of defence for the caterpillars. Because they become toxic too, any predators that try eating them are likely to get very sick. The European Birthwort (A. clematitis) is the species I was expecting to find, so I was pleasantly surprised to find the Round-leaved Birthwort was the local species. Birthworts tend to be straggling plants that need other vegetation or support to climb over. The Aristolochia species have unusual tube-shaped or pipe-shaped flowers, and one species, the Dutchman’s Pipe, which has very large and attractive blooms, is grown for ornamental purposes.

Watching the Desertification of Portugal

Climate Breakdown and Desertification

Dried up pond (Photo: Steve Andrews)
I have been living in Portugal since late 2014 and over the years have been watching the changes in the weather and to the countryside. Every year we have had very hot weather and wildfires and droughts are becoming the new ‘normal’ here due to Climate Breakdown. It is getting worse and I feel I am watching the early stages of the desertification of Portugal.

Ponds Dry Up

Cracked mud (Photo: Steve Andrews)

I am sure that amphibians and other aquatic wildlife are having a hard time due to the lack of water. A river near where I live has run dry in the past and this year some roadside pools have already dried up and are just cracked mud. This is very unfortunate news for the small colony of Iberian Water Frogs that were breeding there. Only a month or so back there were thousands of tadpoles in these pools and Water Starwort was an aquatic plant that was growing.

Iberian Water Frog tadpoles (Photo: Steve Andrews)

Sadly the hot, dry weather has evaporated all the water before the tadpoles could complete their metamorphosis and they have all perished. I had moved some to the deeper pools but it was in vain because they dried up too.

Wildflowers

French lavender (Photo: Steve Andrews)

The wildflowers here are spectacular in spring with so many species bringing a splash of colour to the countryside. French Lavender, Candytuft, Campanula lusitanica, Silene colorata (a bright pink Catchfly), Common Poppies, Three-leafed Snowflake, Narrow-leafed Lupin, St John’s Wort, Crown Daisy, Asphodel, Toadflax, Tassel Hyacinth, Blue Hound’s Tongue, Scrambling Gromwell, and Sage-leafed Cistus are just some of the colourful plants that beautified my country walks back in April and May. It is hard to think that all these pretty flowers were growing well not long ago on ground which is now brown and tinder dry. Where even the grass has died down and the paths are dust.

Flowers in Spring (Photo: Steve Andrews)

Earlier in the year there were countless butterflies. I would expect to see Swallowtails, Red Admirals, Green Hairstreaks, Spanish Festoons, Clouded Yellows, Speckled Woods, Small Coppers, and Small Whites and would never fail to be disappointed.

Green Hairstreak (Photo: Steve Andrews)

A bit later the Meadow Browns became the most commonly seen butterfly but now there are hardly any about.  There are hardly any flowers left from which they could feed and the vegetation has died back or is conspicuously brown and shrivelled up. In the four years before this year I have never seen it so dry and so dead looking as it is now. I live in Quinta Do Conde, a town between Lisbon and Setubal, so am not in the hot south of the country. If it is like this here I dread to think what it must be like in the Algarve.

Skeleton Weed (Photo: Steve Andrews)

But not all plants are doing badly in the hot and dry conditions. Some are colonising new ground and others are adapting. The Skeleton Weed (Chondrilla juncea) is a species that is happy growing in arid places and I see more and more of the plant on waste ground where I live and even growing in cracks in paving. It is an invasive weed that has become a problem in many parts of the world and after wildfires it will rapidly colonise new ground where other vegetation has been killed.
Black Mustard, or a species of mustard that earlier in the season looks very like Black Mustard, is forming bushy clumps when it goes to seed here. They resemble tumbleweeds and can easily break off helping to distribute the plant.

Mustard clump (Photo: Steve Andrews)

Wildfires

As already mentioned, wildfires are becoming a new ‘norm’ for Portugal and can now occur all year round, due to Climate Breakdown and droughts which can now take place even in the winter. These fires, in addition to destroying farms and houses, are killing animals and people, as well as vast numbers of trees of native species. Pines and Cork Oak can regenerate if not too badly burned but when the trees are weakened and if drought continues they become very susceptible to disease. The Pine Wilt Nematode, spread by various wood-boring beetles is killing pines throughout the country. When the rains finally do arrive another problem the countryside faces is the erosion of the fertile top soil that is washed away.

The Portuguese authorities have implemented legal measures requiring landowners to take action by clearing undergrowth,  brushwood and scrub that could easily burn. Many areas where this has been done will have destroyed wildlife habitat and many dormant and active species sheltering in the vegetation. Efforts to provide safety for farmers and residents of Portugal, are surely taking a toll on the flora and fauna of the country.

Permaculture as the Solution

Desertification of Spain and Portugal

I have known about the predicted desertification of Mediterranean countries including Spain and Portugal before I came to live here. Sadly I am now watching the problem in action. I was searching online for information on desertification in Portugal and found this very detailed and excellent lecture by Doug Crouch, who describes how the system of modern farming is degrading the land further. He also proposes permaculture as the solution. He explains what has been going wrong and what can be done to reverse the ongoing growth of what he calls the “New Sahara.”

Everybody’s Talking About American Monarch Butterflies

American Monarchs are in the news

Male Monarch Butterfly, Female Monarch (Photos: Steve Andrews)

Every time the Monarch Butterfly (Danaus plexippus) makes the news it is the latest on the iconic insect’s struggles in America, where it has migrated in billions from Canada and the northern states down to California and Mexico each autumn. Over the past decade there have been reports of the butterfly’s alarming decline, due to habitat loss, pesticides, herbicides, disease and climate change. Modern farming using the herbicide Roundup (Glyphosate) on maize and soya-bean crops, is eliminating the once common milkweed species that grew in farmlands throughout the United States.  Legal and illegal felling of trees in Mexico in areas where the monarch overwintered is another big problem.

A disease known as “OE,” which is the abbreviation for Ophryocystis elektroscirrha, a protozoan parasite, takes its toll on the butterflies causing severe weakness, and cripples with deformed wings that do not live long. Some butterflies are so weak they fail to be able to emerge from their chrysalises, others that do die shortly after. It appears that OE is widely distributed among all Monarch populations. The microscopic spores are spread from infected adult butterflies onto the leaves of milkweed plants. Caterpillars that eat them become infected. OE is not a threat to other types of butterfly apart from other species in the Danaus genus.

It is very distressing to see how badly Monarch butterflies have been doing in recent years, and there is even talk of the butterfly being threatened with extinction.

Saving the Monarch

Conservationists and concerned citizens of America have been doing all they can to halt the decline in Monarchs and to help the butterfly survive in great numbers again. One of the main methods being used is the cultivation of milkweed (Asclepias) species. Many people have taken to growing these plants and rearing the butterflies in captivity by keeping, eggs, caterpillars and chrysalises indoors or in protective enclosures. The idea is to keep them safe from predators, such as wasps.

Tropical Milkweed (Photo: Steve Andrews)

The problem with these methods is that one of the most commonly grown milkweeds known as Tropical Milkweed (A. curassavica) is a non-native species that is suited to tropical and subtropical areas. With warmer weather due to climate change it is being grown in many places where once it would not have survived. It can cause a very real problem because it can build up large numbers of OE spores and become a source of infection. This happens in places like Florida where it is warm enough for the plant to grow all year around. This also means that Monarchs can continue to breed in such areas and will not have any need to fly elsewhere. Many scientists and Monarch conservation and research groups, such as the Xerces Society, are recommending that only native milkweeds should be grown. This is good advice. There are many species of Asclepias that grow in all zones of North America and right up into Canada. These plants die down for the winter and resume growth again the following year. These native species do not allow the build-up of OE on them. These endemic milkweeds encourage the Monarchs to migrate because it means that late in the year there are no food-plants available for the females to lay their eggs on. It was all working really well until humans interfered by destroying milkweeds with herbicide and then, in an effort to help, by growing a plant not native to the north American states. The Tropical Milkweed is getting a bad name but the reason is due to the very real problems it can cause in America. However, in some places there is no other choice!

Elsewhere in the World

Female Monarch on Balloonplant (Photo: Steve Andrews)

Monarchs live in non-migratory populations in many other parts of the world, including the Canary Islands, Portugal, Spain, New Zealand and Australia. In these countries there are no native milkweeds, and indeed, the butterflies have only been able to colonise large areas due to the prevalence of the introduced Tropical Milkweed and two other plants that were formerly in the Asclepias genus. The Balloonplant (Gomphocarpus physocarpus) and the Swan Milkweed (G. fruticosus) are naturalised in all the places named above and are both used as Monarch caterpillar food-plants.

Female Monarch returns to my garden to lay eggs on Tropical Milkweed

I lived in Tenerife in the Canary islands for nine years, and it was there that I started successfully rearing Monarchs. I fed the caterpillars on Tropical Milkweed, which is the only milkweed found on the island, apart from very occasional specimens of the Gomphocarpus species. It is because the Tropical Milkweed was brought to the island as an ornamental garden flower that Monarchs were able to colonise Tenerife, where it is said they were first seen back in 1887. How they reached the islands is uncertain. Now that Monarchs are on Tenerife, they have no need for migration because, although it gets plenty of snow and ice up on Mt Teide, around the coasts and in the south, the temperatures remain warm enough for Tropical Milkweed to keep growing and the butterflies to keep breeding. The situation is similar in parts of mainland Spain and Portugal where this non-native milkweed has been grown in gardens and where the Gomphocarpus species have become naturalised.

Monarch Butterflies in Portugal

Recently eclosed Monarchs (Photo: Steve Andrews)

I have lived in Portugal for the past four years, and this year I was successful in rearing four generations of Monarchs with the caterpillars feeding on plants of Tropical Milkweed and Balloonplant I managed to grow enough of in the garden here. I had at least 30 butterflies each time. The last lot of adult butterflies emerged in late November but where they went I have no way of knowing. I have cut what was left of the milkweeds down to short stalks so if any females came back they would have found nowhere to lay their eggs. I originally obtained eggs from someone I know who has a butterfly farm up in Aveiro further north. He tells me there are no Monarchs there in winter and he gets his eggs sent up each year from the Algarve. According to As Borboletas De Portugal, a Portuguese butterfly book I have, along with the Algarve, the northern coastal city of Aveiro, is one of the only places that Monarchs can be found in the country. Is this because of the butterfly farmer I know there, or are there naturally occurring wild ones, and how did they get there? I have been told that the butterflies can sometimes be seen in the Lisbon area too. Where did they come from? Did they migrate from the south? I often wonder what happens in winter. Do any Monarchs go south here to the Algarve where there are non-migratory populations or do all the butterflies in central and northern parts, such as the ones I released, simply live short lives and fail to breed due to the cold weather and lack of food-plants. There is very little information available online or in books about the behaviour of Monarchs in Portugal and Spain, and indeed in Europe. Is anyone else studying these butterflies here apart from me? Google for information on Monarchs and most of the results are about those in America.

I have had the idea that the non-migratory resident Monarch populations, wherever they are worldwide, are forming a genetic reservoir of the species. If its migratory populations ever do become extinct, the species could be reintroduced by moving some from the resident colonies elsewhere.

The Wanderer

I have wondered whether as climate change causes milder winters would the butterflies colonise other more northerly countries if the non-native food-plants grew in sufficient numbers there? Would any Monarchs eventually evolve into a migratory form like their American cousins? A very small number of Monarchs reach the UK some years but are unable to breed due to lack of any type of milkweed growing there and are unable to survive the cold winters. But the fact that they got there at all reveals their wandering nature, which is why an alternative name for the Monarch Butterfly is the Wanderer.

The Cacti of Iberia

Cacti of Spain and Portugal 

Prickly Pears (Opuntia dillenii)

You will see cacti growing in many parts of Iberia, mainly types of prickly pear cactus, and in some places, such as the Canary Islands, they are so common that it is easy to assume they are part of the native species. They look just right for the semi-desert landscapes. But in fact, there are no endemic cacti in Spain or Portugal, though some species from the Opuntia and Cylindropuntia genera have become widely naturalised. There are actually as many as 20 different types of Opuntia recorded as growing wild in Europe and the Mediterranean, but we are looking at the ones found in Iberia, and the ones you are most likely to see.

Prickly Pears

Harvested Prickly Pears

Cacti in the Opuntia genus are commonly and collectively known as prickly pears. The name refers to their edible fruit, which are found budding from the large and very prickly pads. These cacti have large numbers of tiny spines or glochids that project and will detach easily from the small bumps on the cactus skin that hold them, and which are technically known as aeroles.

There are two main species of prickly pear seen in Iberia: O. ficus-indica and O. dillenii. The first of these is known in English as the Indian fig Opuntia and the Barbary fig. The plant is referred to as “nopal” in Mexican Spanish, and its fruit is a “tuna.” The flowers are red, yellow or white, and the fruits are green, turning yellow or reddish as they ripen. It has been historically grown as a food crop for thousands of years in Mexico. You need to carefully remove the spines on the tunas by rubbing in an abrasive material and also peeling the fruit. They are usually eaten chilled and resemble watermelon in flavour. The fruit are also used to make jams and jellies, and have been used in the production of alcoholic drinks too. You will often see them for sale on fruit and vegetable counters.

The green pads, or nopales, can be eaten too. Again, you must carefully remove the spines, and the sliced pads can be fried or boiled.

Prickly Pear Flowers

The species O. dillenii is also known as O. stricta, and in English it is called the erect prickly pear. It has lemon-yellow flowers followed by purplish-red fruit with smooth skins, though, once again they are protected by spines. I used to eat a lot of these fresh when I lived in Tenerife, and used to manage to safely peel them using my thumb and finger-nails, but it is a tricky procedure so cannot be recommended. The tiny spines are notoriously difficult to get out of you and they hurt! This cactus is actually regarded as an invasive weed in many parts of the world where it has invaded the land. All species of prickly pear spread easily from pads which have broken off from the parent plant but which then root where they have fallen.

Cholla cacti

A very prickly Cholla

Speaking of cacti that spread easily from pieces that have become detached brings me to the cholla cacti in the Cylindropuntia genus. In Spain and Portugal there are two species that are commonly encountered: C. spinosior and C. imbricata. The first of these is known as the walkingstick cactus or the spiny cholla, and the latter species is called cane cholla or chain-link cactus. Both species are well-protected with large numbers of the most vicious spines imaginable all over the sections of the plants. The spines will easily break off, and the sections of cactus can also be readily detached. My advice is be very careful with these plants, because the spines are really painful. Fall accidentally into one of these and you will regret it!

The cholla cacti come from Mexico and the southern states of America but have spread to many parts of the world, where like the prickly pears, they have become invasive weeds.  Although these cacti can be problem plants, they also make formidable fences. Anyone caring to ignore them is asking for trouble!

Peruvian Apples

In addition to the cacti in the Opuntia and Cylindropuntia genera, you may see the Peruvian apple cactus (Cereus repandus/peruvianus) growing in gardens, and also on waste ground in Iberia. This cactus is very tall and produces columns that can easily reach as much as 10 metres in height. It comes from South America but stands up to cold periods in Spain and Portugal well. This cactus produces spectacular cream-coloured flowers that open at night and are only open for the one night. The flowers turn into edible fruit, known as Peruvian apples or pitaya.

Besides all these cacti that might be encountered in Iberia, many gardeners introduce other species into community-used ground near their homes, and cacti often root when they have been thrown out, so you can at times find all sorts of surprises but none are native plants. Gardeners in Portugal and Spain often grow many cacti outside that in the UK are strictly houseplants. The hot summers and mild winters give us an advantage when it comes to cactus growing.

NB: This article was intended as my last contribution to Mediterranean Gardening & Outdoor Living Magazine but due to the co-editor's health, the publication has very sadly had to close down earlier than was hoped and has failed to find anyone to take over running it.

The Pride of Madeira

A Bugloss known as Pride of Madeira

Pride of Madeira in Sintra (Photo: Steve Andrews)

The Pride of Madeira is the common name for a spectacular looking shrub in the Echium genus of plants, many species of which are known as types of Viper’s Bugloss or “Taginaste” in Spain. Known to botanists as Echium candicans, the Pride of Madeira comes, as its name suggests, from Madeira, but it is often grown in gardens and parks throughout Iberia and in many other parts of the world. Its popularity is hardly surprising because it forms a very large bush that is covered in spring and early summer in magnificent flowering spikes of purplish-blue flowers with red stamens. The Pride of Madeira will definitely catch your eye and is very attractive to bees and other pollinating insects too, as are the other species in the Echium genus.

Red Bugloss or Mt Teide Bugloss

Red Bugloss on Tenerife (Photo: Pixabay/Public Domain)

The Canary Islands are home to very many endemic types of Echium and the Mt Teide Bugloss or Red Bugloss (E. wildpretti) is a plant symbolic of Tenerife where it grows high on the mountain it is named after. This unusual plant is a biennial that produces a large rosette of leaves in its first year which is followed by a tall flowering spike in its second year. The tiny flowers are a pinkish-red but there are many thousands of them and its flower spikes can grow to as much as three metres in height. They stand out like weird red wands above the otherworldly and barren terrain on Mt Teide, which is the highest mountain, not only in Tenerife but in all of Spain.

The Red Bugloss is a very rare plant in the wild, and only found on Mt Teide and around the village of Vilaflor which is also high in the Tenerife mountains. The plant has evolved to be adapted to the cold nights and bright sunlight by day of the habitats it is found in, though it is also grown at lower levels of the island in parks and gardens. Because of its tall flowering spikes it is one of the bugloss species often called “Tower of Jewels.”

Giant Viper's Bugloss

The Giant Viper’s Bugloss or Tree Echium (E. pininana) is the best-known Tower of Jewels bugloss. It reaches four metres in height in good conditions, and like the Mt Teide Bugloss is very rare in the wild. It is only found in the laurel forested mountains of La Palma in the Canary Islands, however, it has been commonly grown for some years as an unusual garden flower in the UK and Ireland, where sometimes it gets featured in news stories because it grows so tall.

Wild Viper’s Bugloss species found in Iberia

Viper's Bugloss (Photo: Pixabay)

There are many types of Echium found growing in the countryside of Iberia, including the type species Viper’s Bugloss (E. vulgare), which is found throughout Europe and has become naturalised in North America. It has pinkish flowers which turn rapidly blue and it is also known as Blueweed. It likes to grow in sand dunes and waste places but will often do better in cultivation in the garden where it will get larger. The Viper’s Bugloss, by the way, takes its name from the tiny forked nutlets that it produces that were thought to resemble the heads of snakes, and because it was once regarded as an antidote for the bite of an adder. The herbalist Coles tells us in his Art of Simples: 'Viper's Bugloss hath its stalks all to be speckled like a snake or viper, and is a most singular remedy against poyson and the sting of scorpions.”

One species of Echium that is very common, not only in Iberia but elsewhere in the world is known as Patterson’s Curse (E. plantagineum). Its name gives a clue to how it has become regarded, because although this small species looks pretty when it creates a small sea of purple flowers, it is an invasive weed of arable land that spreads rapidly. Isn’t it interesting to consider how some bugloss types are very rare plants while others are common weeds?

Grow a Tower of Jewels and Feed the Bees and Butterflies

Most species of Echium have a lot of nectar-filled flowers making them very attractive, not only to our eyes, but, as already noted, to bees and pollinating insects. Butterflies too love to find their food in the flowers of a Tower of Jewels. It is easy to find seeds of the various species that are easy to grow in our gardens by searching on the Internet for “Echium seeds” or “Tower of Jewels seeds”.

Growing these amazing plants can not only really beautify our gardens but be a real help to the bees and pollinators that are often struggling in the world today. Cultivating a Viper’s Bugloss provides eye candy and aids conservation!

NB: Text originally published in Mediterranean Gardening and OutDoor Living magazine, Issue 25, May 2016.

Monarch Butterfly Monitoring in Portugal and Spain

Monarch Butterfly Colonies in Portugal and Spain

Monarch (Photo: Public Domain)

I have been wondering what happens to monarch butterflies (Danaus plexippus) that emerge from their chrysalises in the late autumn in Portugal and Spain. I am wondering if there are any organisations or individuals out there that know or are monitoring the colonies and populations of these insects.

Migratory Monarchs

It is common knowledge that these beautiful butterflies conduct an incredible migration from Canada and the northern states of America down to Mexico and California in the south of the US each fall, and then repeat the journey in the opposite direction with the coming of spring.

Overwintering Monarchs (Photo: Public Domain)

The monarchs overwinter in vast numbers that cling to trees. Conservationists have become rightly concerned about the diminishing numbers of monarchs that are arriving to overwinter and that are successfully accomplishing this essential part of their life cycle. Forests in Mexico are being destroyed and freak winter weather due to Climate Change is taking a toll.

In America the subject of monarch migration is being taken very seriously and efforts are being made to monitor the numbers of these butterflies. If you search online for “monitoring of monarch butterflies” you will find plenty of relevant entries for America but not so if you search for “monitoring and distribution of monarch butterflies in Portugal and Spain.” Yes, there are plenty of results but none that I can find that tell you much about the populations in the Iberian countries, only that they exist. It is known that monarchs can be found on the Azores and in Madeira too, as well as the Canary Islands, which count as part of Spain.

Monarchs in Portugal

I have a book I bought in Portugal entitled thebutterfliesofportugal, edited by Ernestino Maravalhas and published by Apollo Books, and it has a distribution map for the monarch butterfly. It is shown as living in the Aveiro area on the northern coast and along the coast of the Algarve in the south.

Monarch caterpillar (Photo: Public Domain)

I have recently obtained some monarch caterpillars from a butterfly farm in Aveiro but the owner tells me there are no monarchs in the north in winter.  I have the food-plants scarlet milkweed (Asclepias curassavica) and the bristly fruited silkweed (Gomphocarpus fruticosus) growing here on which the caterpillars are feeding.

Bristly Fruited Silkweed  (Photo: Public Domain) 

Incidentally it is these plants that have been introduced into Iberia as garden plants that have enabled the monarch to colonise Spain and Portugal. The same goes for Tenerife and the Canary Islands where the scarlet milkweed is often grown as an ornamental garden flower.

Monarch on Milkweed (Photo: Public Domain)

I have successfully reared many monarch butterflies in Tenerife when I lived on the island where there are non-migratory populations, and I know that the insects there continue flying and breeding in the warmer coastal areas through the winter months when it becomes too cold and their food-plants die back in the mountains and higher ground. But I am wondering if the situation is the same in Portugal. If so what temperatures do all stages of the insect need to survive and complete their life-cycle? I estimate my caterpillars are going to need a week more here before they will change into chrysalises and probably a bit longer before they emerge than the ones I have reared before in the slightly warmer part of Tenerife where I lived. I estimate that the butterflies will be emerging late in December but what will they do if I set them free, allowing for sunny and warmer winter days here in Portugal. Will the monarchs attempt to overwinter, will they die doing so or will they fly south?

I have been trying unsuccessfully to find out in searches on the Internet but most information I find is mostly about the migratory monarchs in the US.

I know that the milkweed and bristly-fruited silkweed can continue growing throughout the winter here so the food-plants are available, but I don't know whether it simply gets too cold for any stage of the monarch’s life-cycle to survive.  Anyone reading this who can tell me more about the monarchs in Portugal and Spain, please get in touch or leave a comment.