From ScienceDaily

The painted lady butterfly is a migratory species in Europe, and common visitor to the Channel Islands, previously known to migrate from Europe to the Afrotropics during the autumn. Butterflies are obviously much harder to track on migration than birds and the fate of this butterfly species and its offspring remained unknown. Butterfly migration can be very different to that in birds where a bird like the swallow moves between, often very distant but well demarcated, summer and winter areas. The best known butterfly migration is perhaps that of the monarch in North America where despite there being well known and well demarcated summer and winter areas, generations of monarchs will never see the winter areas but are essential in the species life cycle (see the fascinating story of the monarch here).

Researchers were now able to demonstrate that painted lady butterflies return from the Afrotropical region to recolonise the Mediterranean in early spring, travelling an annual distance of 12,000 km across the Sahara Desert.

While the Palearctic-African migratory circuit is typically associated with birds, scientists from the Institute of Evolutionary Biology (IBE), a joint research centre of the Spanish National Research Council (CSIC) and Pompeu Fabra University (UPF), in Barcelona, Spain, found that the painted lady Vanessa cardui endures annual trans-Saharan circuits like some birds do.

This butterfly species travels 12,000 km and crosses the Sahara Desert twice to seasonally exploit resources and favourable climates on both sides of the desert. Few species are known to perform annual long-range trans-Saharan circuits, and that of the painted lady is the longest migratory flight known in butterflies to date.

In a previously published study, the researchers demonstrated that painted lady butterflies migrate from Europe to tropical Africa by the end of summer, crossing the Mediterranean Sea and Sahara Desert.

The fate of these migrants and that of their offspring remained unknown. “Our hypothesis was that the species initiates a reverse northward migration towards Europe in spring, thus completing a regular migratory cycle,” states Roger Vila, one of the researchers.

The answer is in the wings

With the aim of confirming this hypothesis, they studied the natal origin of the butterflies that reached the Mediterranean region in early spring. To do so, they analysed the stable hydrogen isotopes of the butterflies sampled in Morocco, Andalusia and Catalonia in Spain, Crete, Egypt and Israel.

An isotope is a form of a chemical element whose atomic nucleus contains a different number of neutrons compared to protons in the nucleus. In water, the proportion of hydrogen and its stable isotope depends on the geographical location. When absorbing water, this proportion is maintained in plants; it later remains in the caterpillars that feed on these plants, and, eventually, in adult butterflies.

By analysing the hydrogen stable isotopes found in the wings of adult butterflies, the researchers could determine where they had developed as caterpillars.

“It is difficult to study the movement of insects by means of observations, marking or radio tracking, since there are millions of individuals and they are very small. This is why finding out where a butterfly grew up before undergoing the metamorphosis by means of stable isotope analysis turns out to be extremely useful. It feels like magic,” says Gerard Talavera, who led the research.

The results show a major proportion of specimens stay in the Afrotropics during winter and that those recolonising the Mediterranean are most probably their offspring. This scenario closes the loop for the Palearctic-African migratory system of Vanessa cardui and shows that the annual distance travelled by the successive generations may reach about 12,000 km, including crossing of the Sahara Desert twice.

Whether the painted lady does regular migratory circuits similar to those of the monarch butterfly in North America was a matter of scientific debate. This research reveals the parallelisms in such a unique evolutionary adaptation.

Access the paper Round-trip across the Sahara: Afrotropical Painted Lady butterflies recolonize the Mediterranean in early spring here

From Rare Bird Alert and Ian Buxton

The Shiant Isles have been officially declared rat-free, thanks to a four-year partnership project to restore them as a secure haven for nesting seabirds. A month-long intensive monitoring check in February found no sign of rats. This means that none has been recorded there for two years, the internationally agreed criterion for rat-free status.

The EU LIFE+ funded Shiants seabird recovery project started in 2014 and is a partnership between the Nicolson family, custodians of the islands for three generations, Scottish Natural Heritage and RSPB Scotland. It has benefited from the help of many volunteers, and significant private donations.

Jersey ornithologist and bird ringer, Ian Buxton, first visited the Shiant Isles in 1977, returning in 1980. Since then Ian has made a further five trips during the last 10 years, until this year, his visits have been for two weeks during the summer to survey and monitor the breeding seabirds. In 2009 Ian retrapped a puffin he had ringed there in 1977. Ian’s most recent visit was this February, for four weeks to assist in the completion of the rat eradication programme.

Over the last four years the recovery project has focused on making the islands a safe place for seabirds to raise their chicks by removing the invasive, non-native black rats that were found there. It has been a huge success and played an important role in developing future island restoration and biosecurity work in the UK.

Another key part of the project is a programme of research monitoring the response of the ecosystem to the removal of rats. It is anticipated that seabirds such as puffins, razorbills, and guillemots will see improved breeding successes which could eventually support population increases in these long lived seabirds breeding on the Shiants. It is hoped that Manx shearwaters and storm petrels will begin to nest on the islands as well.

An operation to eradicate the rats was carried out over the winter of 2015/16, led by a New Zealand-based company Wildlife Management International Limited (WMIL), with the help of fifteen volunteers. This stage was incredibly challenging due to the rugged terrain and steep cliffs that make up the islands, and the Hebridean weather conditions including severe storms. Since then regular monitoring for signs of rats has been carried out with none recorded.

As well as the seabirds currently found on the islands, the Shiants offer suitable nesting habitat for European storm petrels and Manx shearwaters, two species of seabirds that are not generally found on islands with rats. Over the last two summers, the project has been working to encourage the storm petrels and Manx shearwaters to nest on the islands. The calling storm petrels, recorded on the islands last summer for the first time, gave a strong sign that the Shiants were free of rats ahead of this recent check.

In order to ensure that the islands remain free of rats, and other mammalian predators, visitors are being asked to follow simple biosecurity measures to help keep the islands rat free. This includes checking boats and all kit for signs of rats prior to departing for the Shiants, and looking out for signs of them when on the islands. Local boat operators along with SNH and RSPB Scotland staff have been trained in biosecurity measures by the project.

Dr Charlie Main, Senior Project Manager for the Shiant Isles Recovery Project said: “This is an absolutely fantastic moment for the Shiant Isles and everyone involved in the project is delighted that they are now officially rat free. With so many of Scotland’s seabird populations in decline it’s vital that we do all we can to help them. Making these islands a secure place for them to breed is really important.

“Over the next few years we’re really looking forward to seeing the full impact of the islands’ restoration flourish with the seabirds enjoying improved breeding successes, and other species beginning to breed there as well. We’ll also continue to work with the local community to ensure this special place remains free of rats. This project has paved the way for more island restorations to take place around Scotland and give our threatened seabirds the best possible chance for the future.”

Andy Douse, Scottish Natural Heritage (SNH) ornithologist, said: “It’s wonderful news that this project has helped to protect the internationally important seabird colony on the Shiant Islands. The partnership between RSPB Scotland, WMIL, the Nicolson family and SNH has been a great success, particularly considering the complexity of the project, and we’d like to thank everyone involved. It was a great team effort, and we can now take the knowledge gained from this project into other work to protect Scotland’s special species and habitats.”

Tom Nicolson said: “”Obviously this is a tremendous story of success on so many levels. When the idea was presented to us six years ago, the pure logistics of the project seemed hugely ambitious. Now, knowing that new species are beginning to thrive on the islands, so soon after the project has finished, there are no limits to what the Shiants could become over the next five, ten, twenty years.

“It has been an immense pleasure working with such a talented and dedicated group of people from the RSPB and Scottish Natural Heritage – everyone involved should be thoroughly proud of themselves.”

Read more about the work of the Shiant Isles Recovery Project

From The BBC

Scientists are warning of the risks of wild birds spreading diseases when they gather at feeders in gardens. Experts led by the Zoological Society of London say people should continue to feed birds, especially in winter, but should be aware of the risks.

A newly published review of 25 years’ worth of data has identified emerging threats to garden birds. Finches, doves and pigeons are vulnerable to a parasite infection and form of bird pox is becoming more common, causing warty-like lumps on the bodies of great tits and other birds while other disease threats, such as salmonella, appear to be declining. If birds look sick, food should be withdrawn temporarily, the authors say.

“Our study shows how three of the most common diseases that affect British garden birds have changed both dramatically and unpredictably over the past decade, both in terms of the species they affect and their patterns of occurrence,” said Dr Becki Lawson from ZSL’s Institute of Zoology.

Common signs that a wild bird is ill include unusually fluffed-up plumage and lethargy. Diseases can be spread through droppings or regurgitated food around bird feeders.

Finding out more about the changing pattern of diseases will help to ensure that garden birds can be fed safely, say the researchers. ZSL, working with experts from the British Trust for Ornithology (BTO), say people who notice sick birds should:

• take practical steps to minimise risks
• report your observations to the Garden Wildlife Health Project
• seek advice from a vet
• withdraw food for a while to let birds disperse over a wider area
• Feed birds in moderation, clean bird feeders regularly, and rotate feeding sites.

Co-researcher Kate Risely from the BTO (BTO News) said anyone who feeds wild birds should be aware of their responsibilities for preventing disease.

She told BBC News: “Be very vigilant – enjoy feeding the birds but educate yourself about what the risks are and what to do if you see signs of disease.”

It was important to continue to feed wild birds, especially in winter, when they need lots of food to survive, she said.

The review found that patterns of infection in wild birds are changing. This may be influenced by wild birds congregating at bird feeders and coming into contact with species they don’t encounter naturally in the wild.

Download the full review Health hazards to wild birds and risk factors associated with anthropogenic food provisioning here

Meanwhile, in Jersey

Changes to a law to try to reduce problems with seagulls and other wild birds are now in place (see update here). Under the Statutory Nuisances (Jersey) Regulations 2017, it’s against the law to feed wild birds or other creatures in a way that means they become a nuisance or harmful to health. Some birds and rodents carry diseases which can be harmful to human health.

Jersey Society for the Prevention of Cruelty to Animals said (BBC 13 March 1256):

• Don’t scatter food on the ground where it is an easy source of food for rodents
• Bird tables can be accessible to rodents. Don’t overstock them or provide large quantities or unsuitable foods
• Use bird feeders with a catch tray to reduce debris falling on the ground
• Site your feeders with care. Suspending them from a metal wire is the only way to be certain rodents won’t get into them
• Ideally, place a small amount of food in feeders daily to ensure they are emptied daily
• Don’t use your garden as a dump for unwanted food waste, the birds may not want it but rats and mice probably will
• Seagulls are protected under the Jersey wildlife law and can only be moved by licensed pest controllers.

The Department said it had taken the action as some birds and rodents carry diseases that can be “very harmful to human health” and gulls were beginning to build their nests and are attracted to places with easily available food.

Anyone found to be feeding (the gulls) illegally would be served with an abatement notice to either stop or restrict their activity. If ignored it would be an offence and the person responsible could be prosecuted.