Weekly round-up: June 27

Turtle dove numbers have plummeted in recent decades (Revital Saloman)

Ornithologists and conservationists hope a year-long hunting ban on turtle doves in Spain will help slow the dramatic UK decline of the species.

The birds, with their distinctive ‘purring’ call and striking mottled wings, have become a rarity on British shores over the past half century, the population falling around 95 per cent from a high of 125,000 breeding pairs. Although the decline is largely attributed to changing land use resulting in a lack of food, the birds also face a hazardous path on their annual migration between Europe and Africa as hunters across Mediterranean countries kill hundreds of thousands of individuals.

This week however, Spanish authorities banned shooting turtle doves in most of the country’s 17 regions.

“This is a really positive step from Spanish authorities because Spain is a key country on the migration route of the species,” said Andy Evans, the RSPB’s head of global species recovery. 

“Hunting exacerbates the problems for these birds caused by agricultural changes, but both problems need to be tackled in order to save the turtle dove. By stopping hunting, turtle doves are given a better chance to recover.”

Research has shown numbers in western Europe could increase by five per cent a year if hunting was stopped along the migration route, but not all countries have implemented bans. In April, the Italian government approved hunting of the birds this autumn. Last year France banned hunting during the 2020-21 migration season following outrage over the continued shooting of birds, but has yet to reaffirm the legislation.

In 2015, the International Union for the Conservation of Nature reclassified turtle doves as Vulnerable to extinction due to their rapidly declining numbers.
Source The Times/BirdGuides

Efforts to boost Tasmanian devil numbers have had unintended consequences on seabird populations

A programme to help boost the Tasmanian devil population in Australia has resulted in the loss of entire seabird populations on an island in the Tasman Sea. Little penguins, which once numbered around 6,000 on Maria Island, have completely disappeared.

Between 2012 and 2013 around 30 devils were released on the island, east of Tasmania. All were free of the deadly devil facial tumour disease, the world’s only known contagious cancer which has threatened the species with extinction. While the Save the Tasmanian Devil Programme operation has been a success – in 2016 the population had risen to around 100 – as predicted by some conservationists and scientists, the introduction has resulted in the complete eradication of little penguins, while numbers of short-tailed shearwater have also been impacted.

“Every time humans have deliberately or accidentally introduced mammals to oceanic islands, there’s always been the same outcome . . . a catastrophic impact on one or more bird species,” said Eric Woehler, convenor of BirdLife Tasmania and a shorebird ecologist. “Losing 3,000 pairs of penguins from an island that is a national park that should be a refuge for this species basically is a major blow.”

He added: “There is an increasing prevalence of resistance to the disease in wild devils. The fact that there are already other insurance populations in existence around Tasmania means Maria Island can be re-established as an island for the penguins and the shearwaters without the devils present.”

Last month conservationists celebrated the birth of the first Tasmanian devils in the wild on mainland Australia in 3,000 years, following the successful reintroduction of a population to the Barrington Tops wildlife sanctuary in New South Wales.
Source CNN

North American migratory birds are getting smaller, and their wings longer – but nobody knows why.

A study by the University of Michigan hypothesised the changes could be due to earlier migrations resulting from climate change, but a study of more than 70,000 individuals across 52 species over four decades showed that while migrations patterns are changing, they were not responsible for the physical changes seen.

Analysing the extensive dataset, researchers found that the first spring migrants were now arriving about five days earlier than in 1978, and the earliest autumn migrants head south about ten days sooner. In addition, the last birds are setting off ten days later, resulting in a significant extension to the autumn migration season.

However, when comparing species-specific rates of migration timing and morphological change, there was no significant link.

“Scientifically, this is really the most interesting and novel finding,” said University of Michigan evolutionary biologist and co-author Brian Weeks.

“It is often assumed that morphological changes driven by climate and changes in the timing of migration must interact to either facilitate or constrain adaptive responses to climate change. But this has never to my knowledge been tested empirically at a significant scale, until now, due to lack of data.”

Further research is required to determine why the morphological changes are happening. Previous studies have suggested that fewer stopovers en route may be a factor, while the team also proposed the changes may allow for faster flight without overheating, reducing water loss.
Publication Journal of Animal Ecology

European water voles are under threat in Britain from habitat loss and predation

In a boon for water vole conservation, scientists at the Wellcome Sanger Institute have successfully sequenced the genome for the European species, helping to better understand their evolution and manage reintroduction programmes.

Once found across Britain and numbering some 7.3 million in 1990, numbers have plummeted to around 130,000 due to predation by the invasive American mink and habitat loss.

Hazel Ryan, senior conservation officer at the Wildwood Trust, said: “Water voles are amazing animals and we don’t fully understand what ecosystems lose without them. They are industrious habitat managers, almost like miniature beavers in the way they fell stems, make burrows and alter the landscape. 

“We suspect that some water vole populations have become inbred in recent decades owing to shrinking numbers and the fragmentation of populations through habitat loss. The reference genome offers us a way to better understand genetic diversity for reintroductions and consider mixing individuals to ensure populations have the best chance to thrive.”

Current conservation efforts include habitat restoration, controlling the mink population, mitigating the effects of development and reintroduction in restored urban and wild habitats.

Professor Mark Blaxter, of the Wellcome Sanger Institute, said: “The European water vole is a prime example of a British species whose genetic diversity we’re in danger of losing before we’ve had a chance to fully record it. This high-quality Arvicola amphibius reference genome will allow us to do that, as well as support ongoing conservation efforts to preserve existing populations and reintroduce new ones in a way that ensures these populations are genetically robust.”
Publication Wellcome Open Research

As seas across the globe warm, many species are shifting their range away from the equator. However, for Florida’s coral reefs spreading north is not an option as climate change is also causing more frequent cold snaps in the Sunshine State.

Coral reefs provide coastal residents with myriad benefits, including storm protection and habitat for fish and crustaceans caught for the food industry. The National Oceanic and Atmospheric Administration estimates that spiny lobster, grouper and snapper which live on and around Florida’s reefs generate $4.4 billion in local sales and support 70,000 related jobs.

The reefs are already listed under the US Endangered Species Act, but erratic weather resulting from climate change is effectively penning them in place, preventing an escape from warming and more acidic seas.

“It’s just not as simple as predicting the corals will move north,” said lead author Lauren Toth, a research scientist at the US Geological Survey. “Thousands of years ago, corals and coral reefs moved north along Florida’s east coast when the climate warmed, but things are different now. Rapid climate change looks to be increasing the number of cold fronts from the polar vortex that are dipping down into Florida.” 

Co-author Richard Aronson, a marine scientist at Florida Tech, added: “All of us on the eastern seaboard know the jet stream is wobbling more and dipping southward more frequently, bringing us bad winter storms and bitterly cold weather. The corals along Florida’s east coast will be hammered from the north by freezes on the anvil of rising temperatures in the south. They won’t be able to shift locations from the Florida Keys to the east coast.”
Publication Scientific Reports

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