Male birds-of-paradise are infamous for their wildly extravagant feather ornaments, complex calls, and shape-shifting dance moves, which have all evolved to attract a mate. New research published in the open-access journal PLOS Biology suggests for the first time that female preferences drive the evolution of combinations of physical and behavioural traits that may also be tied to where the male does his courting: on the ground or up in the trees.
Lead author Russell Ligon, a post-doctoral researcher at the Cornell Lab of Ornithology, suggests that females evaluate not only how attractive the male is, but also how well he sings and dances. Female preferences for certain combinations of traits result in what the researchers call a "courtship phenotype" – bundled traits determined by both genetics and environment.
A female Twelve-wired Bird-of-paradise inspects a male during courtship (Timothy G Laman).
There are 40 known species of birds-of-paradise, most of which are found in New Guinea and northern Australia. Study authors examined 961 video clips and 176 audio clips in the Cornell Lab's Macaulay Library archive, as well as 393 museum specimens from the American Museum of Natural History in New York City. They concluded that certain behaviours and traits are correlated:
As the number of colours on a male increase, so do the number of different sounds he makes.
The most elaborate dancers also have a large repertoire of sounds.
Males that display in a group (called a lek) have more colours to stand out better visually against their competition.
Because female birds-of-paradise judge male quality based on a combination of characteristics, the study suggests that males may be able to evolve new features while still maintaining their overall attractiveness to females – there's room to 'experiment' in this unique ecological niche where there are few predators to quash exuberant courtship displays.
The researchers found that where a bird-of-paradise puts on his courtship display also makes a difference. Edwin Scholes, study co-author and leader of the Cornell Lab's Bird-of-Paradise Project, explained: "Species that display on the ground have more dance moves than those displaying in the treetops or the forest understory.
"On the dark forest floor, males may need to up their game to get female attention. Above the canopy, where there is less interference from trees and shrubs, the researchers found that males sang more complex notes, where they are more likely to be heard. But their dances were less elaborate – perhaps a nod to the risks of cutting footloose on a wobbly branch."
Successful captive breeding has offered hope for the Critically Endangered Plains-wanderer. Deemed Australia's 'most important bird', it is the only living member of the Pedionomidae family and, with fewer than 1,000 mature individuals remaining in the wild, the recent hatching of four healthy chicks represents a lifeline for the future of the species.
The young birds – named Clinton, Jane, Quagmire and Ramble – hatched on 4 November at the Werribee Open Range Zoo, marking the first successful captive breeding of Plains-wanderer in Victoria. The Critically Endangered species is endemic to Australia, found only in the south-eastern part of the country, and the already-small population – now almost entirely restricted to strongholds in Victoria's northern plains and the Riverina of New South Wales – is currently in decline.
Plains-wanderer has declined by more than 90 per cent during the last decade (commons.wikimedia.org).
Given that they are the final remaining species from the Pedionomidae family and Pedionomus genus, some scientists deem their conservation the most urgent of any bird in the world, and Plains-wanderer currently sits in first place on the Zoological Society of London's Evolutionarily Distinct and Globally Endangered (EDGE) bird list. During the past decade, populations in Victoria and New South Wales have declined by more than 90 per cent.
It is hoped that the chicks will one day be released into the wild, as part of a national plan set up two years ago in response to the growing decline of the species. Habitat loss is a key factor behind the dwindling population of this previously widespread bird, as well as the species' ground-nesting habits, poor flying ability and tendency to run rather than fly, which means that they're heavily predated by the introduced Red Fox.
Werribee Open Range Zoo threatened-species keeper Yvette Pauligk said: "Plains-wanderer used to be widespread across Williamstown, Werribee and all across the plains out that way. This species should be in our backyard. The hatching of the four chicks is a huge step for the captive breeding programme, but at the end of the day this isn't going to save the species – if there is no suitable habitat, we can't release them anywhere."
The disappearance of wetlands is behind the extinction of various animals and plants, as well as contributing to the world's imminent failure to reach its 2020 global biodiversity targets, according to a contingent of global NGOs, including the Wildfowl and Wetlands Trust (WWT).
The message, delivered to the UN's Convention on Biological Diversity (CBD) worldwide meeting, currently underway in Egypt, stressed the importance of wetlands to biodiversity, along with the need to create new habitats in order to reverse negative trends.
Wetlands, such as the Biebrza National Park in Poland, are crucial for biodiversity (commons.wikimedia.org).
Wetlands are disappearing three times faster than forests, with a third of the world's wetland sites having been destroyed during the last 50 years. WWT and five other NGOs are global advisers to the Ramsar Convention on Wetlands, whose Secretary-General Martha Rojas Urrego delivered the message to the meeting in Sharm El Sheikh. She said the CBD needs to reflect the priorities of all biodiversity-related conventions, which in the case of Ramsar means restoring and forming new wetlands to support life.
The meeting is being attended by more than 8,000 delegates from around the world – including the UK – in order to establish how to limit losses before the 2020 deadline for biodiversity targets and to plan towards the next deadline in 2030. The CBD is currently working towards a vision of "living in harmony with nature" by 2050.
So far, the CBD had helped governments agree to protect 15 per cent of the world's land and 6 per cent of its oceans. However, the efforts are still not slowing the rate of species extinction, with the CBD's warning of a forthcoming "irreversible tipping point".
WWT Director of Conservation James Robinson said: "Every species of animal and plant depends on the services provided by other species to survive. The more species we can save, the healthier the world will be. We know first-hand at WWT that saving individual species by themselves is not enough; you have to fix their environment and support all the species that co-exist. So, turning the current massive wetland losses into massive gains, by protecting existing wetlands, repairing damage and building new ones, could be our best chance post-2020 to slow the alarming rate of species extinction."
A new YouGov survey has revealed that 63 per cent of Britons want tougher legislation to safeguard the environment. The survey, conducted by the RSPB, also found that seven out of 10 British people would like to see an independent body set up to enforce environmental laws, and nine out of ten (88 per cent) felt we have a shared responsibility to protect the planet.
The survey comes following more than a year of closed-door meetings between environment ministers – including one this week – and the RSPB is now calling on the UK Government to provide more information on environmental policies post-Brexit. Next year is a crucial time as laws, protections and targets will be written and set by the governments of the UK, as well as an overhaul of the agriculture system, so that it farmers, consumers, rural communities and farmland species are catered for.
Farmland species, such as Corn Bunting, have suffered drastic declines, with increased pesticides, loss of mixed farming and changes in crops grown some of the key factors behind the falling numbers (Chris Mayne).
The strength of the new legislation will depend on environmental watchdogs covering England, Northern Ireand, Scotland and Wales that have the power to uphold said laws, as well as ensuring binding targets are achieved. The survey found that 68 per cent of people supported the creation of a national body – independent from government – that would be responsible for implementing and maintaing the laws. As a result, the RSPB have called for a world-leading independent environmental watchdog to hold government to account.
Martin Harper, RSPB conservation director, said: "The public clearly cares about our natural world and we are all looking to politicians to put in place all the protections it requires. Despite some encouraging words about creating world leading environmental legislation, there have been no firm details about how this will be achieved. It is concerning that – as decision-makers and scientists from around the world meet in Egypt for the last Conference of the Parties to the Convention on Biological Diversity before world leaders gather in Beijing in 2020 – the UK is not taking the opportunity to lead the discussions about how we can ensure more of our land is well-managed for nature.
"Over the next 12 months we have an historic opportunity to shape a future in which wildlife and our natural world can thrive. We need governments across the UK to step up their ambitions and establish world-leading new laws that will drive the recovery of the nature on our doorstep – and in doing so, inspire other countries to act."
A new report demonstrates how tailor-made farm wildlife plans – partially devised by Wildlife Trust advisors – has resulted in population upsurges of species like Common Linnet, Silver-washed Fritillary and Brown Hare on Jordans Farm Partnership land.
In 2018, a group of more than 40 Jordans oat growers farmed over 15,500 hectares, devoting around 30 per cent (4,600 hectares) of their land to wildlife. Hedgerows, field margins and ponds have been established in these nature-friendly areas, creating vital corridors to enable animals to spread out and move through the landscape.
Habitat management on Jordans Farm Partnership land has led to increased numbers of the Red-listed Common Linnet (Gary Watson).
Stephanie Hilborne, CEO of The Wildlife Trusts, said: "We are hugely impressed with the commitment of these cereal farmers to support wildlife and the environment, which will benefit generations to come. They are playing an important role in nature's recovery.
"We hope other farmers will take inspiration from them and follow their lead; it shows that farming that works with nature makes sense. The Jordans Farm Partnership demonstrates we don’t have to choose between wildlife and profitable food production. We live in one of the most nature-depleted countries in the world and as more than 70 per cent of our land is farmed, The Wildlife Trusts want to see farmers properly rewarded for creating and restoring habitats."
There are 42 farms in the Jordans partnership and each one works with an advisor from their local Wildlife Trust, together creating a tailored plan to assist local wildlife, focusing on key species and habitats. Winter cover crops are grown to provide food for farmland birds and stubble is left in fields, the latter particularly beneficial to Common Linnet, Corn Bunting and Tree Sparrow.
Voles, and species like Barn Owl that rely on them, have benefited from long grass that's been allowed to grow around field edges. Many grass margins support insects, with their larvae food for the chicks of both partridge species, Northern Lapwing and Yellowhammer. On one farm in Hertfordshire, a recent survey revealed the largest-known counts of Common Linnet and Brambling for the county – proof of the significant benefits nature-friendly farming can provide.
Paul Murphy, CEO of Jordans Dorset Ryvita Company, said: "The Jordans brand has a long-standing commitment to nature and our work supporting conservation in the British countryside dates back over 30 years. We are immensely proud of the Jordans Farm Partnership and the positive impact it is having on much loved farm species such as owls, hares and bats. It is endlessly gratifying to see the passion and devotion our growers have shown to developing habitats and species on their farms and this report is a testament to what they have achieved."
Leaving grass to grow long around field edges is beneficial to rodents, as well as species that prey on them, such as Barn Owl(Maria Schusler).
Following BirdLife's annual update to the IUCN Red List of Threatened Species, Northern Bald Ibis has been removed from the Critically Endangered category, bringing the number of bird species rescued from the brink of extinction since 2000 up to at least 26.
Pink Pigeon is another species that has been downlisted – now classed as Vulnerable – following decades of invasive species control and habitat restoration on Mauritius. However, despite the positive status changes, the IUCN Red List update also reflected the harsh reality of the growing challenges in conservation, with a host of species placed in higher threat categories.
Northern Bald Ibis has been reintroduced to Andalucia, where a free-flying colony now exists near Vejer de la Frontera (Paul Coombes).
Prior to the 2018 assessment, Northern Bald Ibis was among 222 Critically Endangered bird species, all with a genuine threat of extinction. As recently as 1998, only 59 pairs remained, almost exclusively confined to the Souss-Massa National Park in Morocco. However, a range of conservation measures – including the employment of local fishermen to protect the birds – has seen the population rise to nearly 300 individuals, some of which spread to two new breeding sites last year. Such numbers are still low and the ibis is still categorised as Endangered, but semi-wild populations in Turkey and high-profile captive release programmes in Spain offer hope of continued recovery across its former range.
In 2000 Pink Pigeon was considered Critically Endangered, but steady conservation management has seen the species moved to Vulnerable in the latest update. Twenty-eight years ago, just 10 Pink Pigeons remained in the wild, but a captive breeding programme, as well as intense field conservation, mean there are now an estimated 400 individuals. Further good-news stories come from North America, where Red-headed Woodpecker and Henslow's Sparrow – previously Near Threatened – have both been downlisted to Least Concern following habitat restoration.
Habitat loss and introduced predators, such as Black Rat, Crab-eating Macaque and Small Indian Mongoose, had reduced the wild Pink Pigeon population to just 10 individuals (Jaz).
Although the Red List update provides demonstrations of conservation success, there were also many examples of negative trends. No fewer than eight species of hornbill have been moved to higher threat categories, mainly due to deforestation and hunting. Most of these species reside in the Sundaic lowlands of South-East Asia, where rates of deforestation are highest. In a vicious circle, forest loss is also making it easier for hunters to access these birds. Larger species such as Great Hornbill and Rhinoceros Hornbill are often shot because they are mistaken for the Critically Endangered Helmeted Hornbill, whose casque is highly desirable on the black market.
Great Hornbills are often shot, having been misidentified for Helmeted Hornbill (Roger Ridley).
Also in South-East Asia, Java Sparrow and Straw-headed Bulbul have been uplisted to Endangered and Critically Endangered respectively; these two species are some of many that are heavily persecuted for Asia's songbird trade, with the sparrow having disappeared from vast swathes of its former range.
Eastern Whip-poor-will and Rufous Hummingbird, both familiar in the Americas, have been moved to Near Threatened following the update. These two species have long been considered common and widespread, so little previous research into the health of their populations had been carried out before. However, long-term monitoring via citizen science projects has revealed that Eastern Whip-poor-will declined by an alarming 60 per cent between 1970 and 2014. Both this species and Rufous Hummingbird rely heavily on insects, so pesticides and intensified agriculture are key factors behind their respective declines.
Pesticide use, intensified farming and climate change are all having a detrimental effect on Rufous Hummingbird (Tom Malarkey).
Melanie Heath, Director of Science, Policy and Information at BirdLife International, said: "This year's list shows that, given sufficient resources and political will, species can recover and habitats can be restored. However, still more concerted effort is required to reverse the downward trends of our planet's most threatened bird species. Governments have a particular responsibility to implement policies that scale up existing successes and achieve environmentally sustainable development to end the biodiversity crisis."
The update thus offers both hope and cause for concern. While it's clear that, with hard work and careful planning, some species can come back from the brink, many more remain exposed to a myriad of threats – the vast majority of which are human driven – on Earth. Such pressures mean mainland bird extinctions are now on course to outpace island bird extinctions for the first time and so targeted, species-specific interventions alone will not be enough. As a result, large-scale international collaboration between NGOs, governments, businesses and local communities is required, along with robust policies to protect the world's most important sites for nature.