Good looks alone are not enough for female birds-of-paradise

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."

Captive breeding boost for Plains-wanderer

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."

Wetland loss driving extinctions

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."

Two-thirds of Britons want stronger laws to protect the environment

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."

Nature-friendly farmers aid wildlife recoveries

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).

Northern Bald Ibis no longer Critically Endangered

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.

Oare Marshes

Fears for Brazilian Amazon as far-right leader prepares for office

Brazil's president-elect, Jair Bolsonaro, plans to merge the environment and agriculture ministries in a move which many fear will put short-term business gain ahead of the long-term global battle against climate change.

Bolsonaro, who will be sworn into office in January, promised that he would merge the two ministries during his election campaign in order to ensure that production (and the prosperity it brings) takes priority over environmental protection. Although subsequently hinting that he might reconsider, a statement this week suggested that the plan still remains. This will please Brazil's huge agri-business and mining lobbies, who were among Bolsonaro's strongest backers because of their desire to open up and exploit the Amazon, Cerrado savannah and other protected areas.

Bolsonaro, who has also promised to relax gun laws and has previously joked about killing his left-wing opponents, is widely considered by conservationists to represent a clear and current danger not only to Brazil, but to the entire planet. His position on the Paris Agreement, a climate accord which aims to reduce carbon emissions and consequently ensure that global warming remains under 2 degrees celsius, remains unclear. Although initially claiming that he'd pull Brazil out, he subsequently stated that he would remain on the condition that there were no restrictions placed on Brazil opening up the Amazon for resources. This in itself is something of an oxymoron, given that preserving the Amazon as completely as possible is vital in any attempt to meet Brazil's targets, as set out in the Paris Agreement.

Satellite imagery showing deforestation in Rondônia, Brazil, in August 2016 – fires burn, clearing hectares of rainforest in preparation for farming and grazing. Despite being closely monitored, illegal forest clearance continues unabated (Planet Labs Inc).

The president-elect's position of business over biodiversity is of great concern to conservationists worldwide. He has already made strong statements about ways to exploit Brazil's natural resources, such as stating his opposition to a policy of reserving 12 per cent of the country's land for indigenous tribes. More land and environmental defenders have been killed in Brazil than any other country – and, with an anti-environmentalist in office from January, the fear is that this worrying statistic will become even more pronounced as criminals feel increasingly confident to use more violence against forest-dwellers.

With the US currently run by a Republican party full of climate-change sceptics and deniers, and China recently starting to peel away from its green position, the focus now falls on Europe to take a lead. Deforestation is largely driven by demand for land to grow soybeans, which are exported to feed livestock, and to expand cattle farms, and there are now calls for the EU to introduce laws which ensure that any imports are not linked to deforestation or human rights violations. The coming years could well be some of the most turbulent in Brazil's – and the world's – recent history.

Review of the Week: 31 October-6 November

In a week in which October turned to November, there was enough excitement to reassure birders that this peculiar autumn still has some life in it yet. This was most acutely – and absurdly – illustrated by Friday evening's news of a Tengmalm's Owl at an undisclosed site somewhere in Orkney.

The associated photograph, of a rather surprised owl perched on a toilet seat, itself covered in detritus. The quantity of droppings suggested it had been there a while, but what would an exceptionally rare owl be doing in someone's toilet? The fact of the matter is that, at the moment, we don't really know much more about the circumstances of this bizarre occurrence, but presumably it will be written up somewhere in due course.

Orkney has a strong track record with Tengmalm's, with five of the seven accepted previous records since 1950 occurring on the islands, two of which were in spring, two in autumn and one in the depths of winter. As well as the legendary suppressed bird at Spurn, which was possibly present for months at the point there in early 1983, the species has a habit of proving untwitchable (either due to news being kept quiet or the individual birds perishing), and this latest record seemingly continues the unfortunate trend.

High-quality Siberian finds this week included a brief Dusky Thrush at Easington, East Yorks, early afternoon on 4th. Almost mythical in terms of its British status prior to the well-twitched Margate bird in May 2013, a further four individuals (including this week's bird) have since followed in just over five years. Another welcome discovery was a flyover Blyth's Pipit on St Mary's, Scilly, on 31st, which was later pinned down and showed intermittently to 4th.

Perhaps the stand-out record for the week, though, was a White-billed Diver in full breeding plumage off the north-east Kent coast. Found off Ramsgate during the late afternoon of 2nd, it spent the entirety of 3rd off Foreness Point before switching its favoured patch to the north-facing coast between Margate and Minnis Bay from 4-6th, often showing extremely well in the process. Any White-billed Diver is extremely rare in Kent, so to get a bird in near-immaculate breeding condition lingering and showing so well makes it a sure-fire highlight of the year for many local birders.

White-billed Diver, Foreness Point, Kent (Stephen Ray).

White-billed Diver, Margate, Kent (Steve Ashton).

Another White-billed, this time in winter plumage, was discovered off Shoalstone Point, Brixham, Devon, on 4th – many birders will fondly remember seeing a confiding bird here in winter 2013/4, some of which enjoyed it on the same day as a Brünnich's Guillemot at Portland Harbour. Back to this week and further White-billeds were seen off Rubha Ardvule, South Uist, on 31st and both Lamba Ness, Unst, and Kirkabister, Shetland, on 2nd. Meanwhile, the Pied-billed Grebe was again noted at Loch Feorlin, Argyll, on 6th (the first report of it since August), and the Shetland bird remained at Loch of Spiggie.

White-billed Diver, Shoalstone Point, Devon (Mike Langman).

A Richardson's Cackling Goose was again reported from Oronsay, Argyll, on 31st. In Highland, two Todd's Canada Goose were at Munlochy Bay on 5th, with the blue-morph Snow Goose still there on 1st. Black Brant were noted in Dorset and Norfolk. The American White-winged Scoter was again noted off Musselburgh, Lothian, on 31-1st, while the Black Scoter continued to show well off Cheswick Sands and Cocklawburn Beach, Northumberland, throughout, often in the company of just a handful of Common Scoter. Musselburgh also bagged a Surf Scoter; another flew past Bull Bay, Anglesey, on 31st and two drakes remained in St Andrews Bay, Fife. Norfolk's King Eider remained stationary off Sheringham throughout. Five American Wigeon included a new bird reported at Cottam, Notts, on 3-4th, but just four Green-winged Teal were logged. Seven Ring-necked Duck and the Anglesey Lesser Scaup completed the wildfowl roll-call.

King Eider, Sheringham, Norfolk (Ian Bollen).

A Snowy Owl in the hills west of North Roe, Shetland, on 4th may well be the bird seen on Fetlar back in October. Meanwhile, in Orkney, the male was again seen on Eday.

It would be fair to say that a major invasion of Rough-legged Buzzards is underway, with no fewer than 40 sites logging the species. The influx was widespread, with birds reported as far north as Highland and Lothian, but also as far south-west as Dorset (Portland Bill on 31st) and Devon (Lundy on 1st). Typically, the east coast between Yorkshire and Kent bore the brunt of arrivals, with the Horsey area of Norfolk logging up to four individuals and two seen concurrently from Rainham Marshes, London, on 31st.

Rough-legged Buzzard, Dartford Marshes, Kent (Oscar Dewhurst).

It would be reasonable to speculate that the juvenile White-tailed Eagle flying north over the Humber at Spurn, East Yorks, on 2nd and latterly seen at Holmpton and Flamborough Head (where it roosted) that afternoon is the bird seen in Norfolk last week. One wonders if it might be a Scottish bird, given it was still on its way north on 6th, having been relocated at Kildale, North Yorkshire.

A good showing of five Lesser Yellowlegs included new birds at The Midrips, East Sussex, on 3-4th and Tacumshin, Co Wexford, on 4-5th in addition to those still in Cornwall, Dorset and on Skye, Highland. The Baird's Sandpiper hung on at Goldcliff Pools, Gwent, to 3rd, while five White-rumped Sandpipers were split between two Irish sites: three were at Roe Estuary, Co Derry, on 4th and two lingered at Tacumshin. The only American Golden Plover was a juvenile still on Benbecula, Outer Hebrides, to 5th, while the sole Long-billed Dowitcher was again the adult at Frampton Marsh, Lincs. In Durham, the Spotted Sandpiperremained on show at Jarrow, Durham, throughout. The Cornish Temminck's Stint was last noted at Stithians Reservoir on 1st.

Lesser Yellowlegs, The Midrips, East Sussex (Richard Bonser).

Spotted Sandpiper, Jarrow, Durham (Mark Fullerton).

In Pembrokeshire, an adult Bonaparte's Gull was watched at Gann Estuary on 4-5th. A juvenile Kumlien's Gull was identified on North Ronaldsay, Orkney, on 4th. Just four sites noted Iceland Gulls; the adult in Troon harbour, Ayrshire, is presumably a returning bird. Glaucous Gulls were more numerous, with at least 15 noted, including a juvenile as far south as Weymouth, Dorset. Some 40 Caspian Gulls were seen, mainly across central and eastern parts of England, but with notable exceptions: a second-winter commuted between Marazion and Hayle Estuary, Cornwall, while a first-winter was a very significant find at Donnybrewer, Co Derry, on 4th.

Caspian Gull, Dungeness NNR, Kent (Richard Bonser).

In the mild conditions, it was no great surprise to see a series of late-season swifts make appearances in southern parts. Confirmed Pallid Swifts graced Skokholm, Pembs, and North Foreland, Kent, on 4th (the latter having roosted in nearby Margate overnight), with modern digital photography yet again proving its worth by enabling high-quality images to confirm identification. Prior to this, two presumed Pallids were over The Naze, Essex, on 1st and a Common/Pallid Swift had flown over Salthouse and Cley, Norfolk, on 3rd, with another briefly at Black Down, West Sussex, on 31st.

Pallid Swift, Skokholm, Pembrokeshire (Skokholm Warden).

Further products of the southerly airflow were three Hoopoes. On 1st, birds were noted at Escrick, North Yorks, and Shaugh Prior, Devon, while another at Hilmarton, Wilts, on 5-6th had apparently been present for a few days prior to it first being reported.

It was almost a surprise that the conditions didn't produce a Desert Wheatear or two, but last week's female Pied Wheatear remained on Foula, Shetland, throughout and another, a male, was identified along the seafront at Meols, Cheshire, on 6th, by which point it had already been present two days – this was a very welcome county first. Meanwhile, in Norfolk, the Stejneger's Stonechat prolonged its already lengthy stay at Salthouse, Norfolk, by another seven days.

Pied Wheatear, Meols, Cheshire (Mark Woodhead).

Stejneger's Stonechat, Salthouse, Norfolk (Tom Hines).

Another typical early November arrival was a Hume's Leaf Warbler at Durlston Country Park, Dorset, on 6th – the first in the country this autumn. A total of four Pallas's Warblers were seen, with arrivals at Beachy Head, East Sussex, and Landguard, Suffolk, on 5th both lingering into the following day and thus proving twitchable (others were seen in Kent and East Yorkshire). A total of five Dusky Warblers were seen, including one showing fairly well at The Naze, Essex, from 31-2nd, two on St Mary's, Scilly, and two found on 6th, in Dorset and Durham. Siberian Chiffchaffs were seen at 15 sites, while Yellow-browed Warblers remained quite numerous in the southern half of our isles.

An Isabelline Shrike performed well at Birling Gap, East Sussex, on 2nd, but couldn't be found there the following day, while there was a report of a Rustic Bunting at Kilnsea Wetlands, East Yorks, on 2nd. Four Little Buntings were seen, with birds in Co Cork, Scilly, Cornwall and East Yorkshire. After last week's influx, just three Coues's Arctic Redpolls were seen. In Norfolk, birds remained at Blakeney Point to 31st and Wells Woods to 2nd, while North Ronaldsay, Orkney, bagged one on 5th. On Unst, the Hornemann's Arctic Redpoll was still at Lamba Ness on 31st. Interestingly, a group of seven Parrot Crossbills was reported at Horsford, Norfolk, on 6th. Two European Serins graced St Mary's, Scilly, on 5th, while two Common Rosefinches were in the Outer Hebrides and a third was trapped and ringed at private site in East Sussex.

Isabelline Shrike, Birling Gap, East Sussex (Beachy Birder).

Yellow-browed Warbler, Easington, East Yorkshire (C Corbidge).

Three of the week's five Rosy Starlings were in Wales, with new birds near Llanelli, Carmarthen, and at Pen-y-Sarn, Anglesey, in addition to the lingering first-winter in Llandudno, Conwy. Others were noted in Cornwall and Somerset. Barred Warblers numbered around 10 and four Red-breasted Flycatchers were seen on 31st, although just one of these lingered into November (at Fife Ness), while 12 sites across England and Wales logged Great Grey Shrikes. Around a dozen Richard's Pipits included an inland flyover at Rawmarsh, South Yorks, on 31st. The Olive-backed Pipit was last seen on St Mary's, Scilly, on 4th.

Great Grey Shrike, Flamborough Head, East Yorkshire (andy hood).

Focus on: Rough-legged Buzzard

With a complete circumpolar distribution, Rough-legged Buzzard breeds across the tundra and taiga of North America and Eurasia, between latitudes of 61° and 76° N. Eurasian birds migrate south to lower latitudes across Europe and Asia to spend the winter, while the North American subspecies sanctijohannis winters in southern Canada and the central United States. The largest subspecies, kamtchatkensis, is found in north-east Siberia and Pacific North America. 

Generally speaking, Rough-legged Buzzard is a scarce winter visitor to Britain, although this status varies considerably from year to year. Occasional large influxes occur, more often than not when a good lemming and vole year in Fennoscandia triggers a bumper breeding season, resulting in large numbers (mainly juveniles) dispersing south-west in the autumn. In these years – which occur perhaps on an average of every six to eight years – Britain can sometimes enjoy bountiful showings of the species. Autumn 1974/75 was arguably the greatest, when up to 250 birds were recorded in October alone. More recently, in 2010, there were over 100 reports during October and November, including four flying in off the North Sea at Spurn, East Yorkshire, on 17 October.

At the time of writing, it seems that another Rough-legged influx could be on the cards. Between 28 September and 31 October 2018 there were 34 sightings; compare this with just three confirmed records during the same time frame in 2017. This apparent influx is mirrored in Dutch records, too – 63 have been tallied over Trektellen vis-mig sites this autumn, and they're seemingly still coming – on 31 October, counts of seven and four were made at separate locations in the north of the country.

The number of Rough-legged Buzzards seen in Britain varies year on year. While virtually none were seen in winter 2017/18, the early indications are that 2018/19 is set to be much more productive for the species (Graham Catley).

Where to look

Typically for a Scandinavian migrant, the vast majority of British Rough-legged Buzzards occur in the east of Britain, with records few and far between in western areas. In Ireland, Rough-legged Buzzard is a genuine rarity, with just 47 records of 49 birds, the last of which was in Co Wicklow in winter 2011/12. Furthermore, one of these birds has been definitively identified as Nearctic santijohannis, with at least a couple of others suspected to belong to this subspecies (more on Nearctic birds can be read here). Coastal marshes and farmland are a big hit with wintering birds, as well as newly arrived individuals. While the North Kent Marshes and north Norfolk traditionally enjoy a decent track record for hosting the species, there are few sites where they can be deemed truly 'regular'. Indeed, any suitable open habitat on the east coast from Scotland down to Kent is well worth searching. 

In bumper years, Rough-legged Buzzards are naturally more widely spread, and can even be found inland or further south and west than normal (for example, there've already been records from Portland Bill, Dorset, and Titchfield Haven, Hants, in October 2018). Consequently, any area of open downland and arable farmland that supports abundant rodent prey could come up trumps. Essentially, any habitat that looks favourable for harriers or Short-eared Owls can be deemed a good place to start looking for Rough-legged Buzzard.

Rough-legged Buzzards tend to favour areas of open or rough ground, where the vole supply is plentiful. They can be located sitting watchfully on favoured perches and, as with other tundra species, are often quite tame – like this juvenile in Essex in October 2015 (Jay Ward).

Identification 

The highly variable plumage of Common Buzzard renders safe Rough-legged Buzzard identification a thorough process. Away from the east coast in particular, pale Common Buzzards are far more likely, even in influx years, and pale Common Buzzards can perform incredible Rough-legged look-alike acts. That said, a classic juvenile Rough-legged Buzzard – certainly if seen well – is quite striking, and can be called on an amalgamation of key features.

If scanning a large area, one may initially be drawn to a consistently hovering Buteo with somewhat lethargic wingbeats, or a hanging bird twisting its tail in a way reminiscent of a Red Kite. Rough-legged is somewhat bulkier and longer-winged that Common Buzzard, and shows a distinct bend at the carpal joints that creates a flattened-down appearance of the primaries, quite unlike the classic V-shape often seen in Common.

This photo perfectly illustrates the flight action and appearance of Rough-legged Buzzard: rather more long winged than Common Buzzard, the bird shows the classic 'bend' at the carpal joints and is also twisting its tail, rather reminiscent of Red Kite (Oscar Dewhurst).

In terms of plumage, it's best to focus on juveniles, given the majority of birds we get in Britain are this age. Five important features stand out:

• A bright white tail and uppertail coverts contrasting with a black terminal band. When viewing a bird from above, the band is thick and dark, but from below far less obvious, narrower and diffuse. Common Buzzards rarely show a clear-cut black and white tail.
• A buff-white head and breast that are strikingly at odds with a very dark, chocolate-brown belly. This can make juveniles appear almost pot bellied at times.
• Solid blackish carpal patches on the underwing. These are small, slender patches or marks on pale Common Buzzards.
• A pale, whitish panel at the base of the upper primaries, which is very rare in Common Buzzard.
• Thick black tips to the underside of the outer primaries, but dusky and narrow tips to the underside of the inner primaries and secondaries.

This juvenile Rough-legged Buzzard exhibits several tell-tale plumage features, including the buffy-white head contrasting with chocolate-brown belly, blackish carpal patches contrasting with largely pale underwing and contrasting black-and-white uppertail, as well as the feathered tarsus that give the species its name (Helge Sorensen).

The tail band is a good way of ageing Rough-legged Buzzards, though adults (particularly males) can also be told by their darker heads, and both adult male and female birds lack the white panel on the upper primaries. Adult males and females can have a variable pale crescent between the belly and neck, a feature typical of Common Buzzards, and the brown tones of all Rough-legged Buzzards tend to be colder than Common Buzzard. The underwing coverts on juveniles are generally a lot less marked than in adults, adding to the pale appearance. If a bird is perched, and views are good, the diagnostic feathered lower tarsus may be made out. A combination of the key features, as well as location and behaviour, is crucial in ruling out a pale Common Buzzard.

Adult male Rough-legged Buzzards are less distinctive than juveniles when viewed from below. However, note the largely white tail (with clearly demarcated black tip) and dark brown gorget contrasting with paler crown and solid dark colouration to the carpals, as well as structural qualities (Steve Young).

Mountain birds 'are on an escalator to extinction'

Researchers retracing the steps of a 1985 expedition in the Peruvian Andes have documented how the area's bird populations have shifted – and in some cases disappeared altogether – due to warming temperatures in the intervening 30 years.

"Mountaintop species are running out of mountain," explained zoologist Benjamin Freeman, lead author of the study in the Proceedings of the National Academy of Sciences. "The next step is extinction. Of the 16 mountain-top species found in the 1985 survey, eight are missing from our new survey."

The researchers believe there is a high statistical probability that at least four species have been extirpated from the survey area, given the team's extensive field searches and analyses of audio recordings. The missing birds are Variable Antshrike, Buff-browed Foliage-gleaner, Hazel-fronted Pygmy-Tyrant and Fulvous-breasted Flatbill. Though none of these species is considered threatened and they are fairly widespread, this research supports the idea that birds living at higher altitudes are moving even higher in reaction to climate change, which can result in local extinctions.

Montane species, such as Variable Antshrike, are already suffering local extinctions in some areas of the Peruvian Andes as a direct result of global warming (Tim Dean).

Freeman led the resurvey of Cerro de Pantiacolla, a 1,415-metre ridge in southern Peru, covering the same ground and employing the same methods used in 1985. Cornell Lab of Ornithology director John W Fitzpatrick led the 1985 survey and co-authored the new report.

"This is the first field-work evidence to show that some local bird populations were literally wiped out by upslope shifting," summarised Fitzpatrick. "We think this pattern is probably being repeated on tropical mountain slopes all over the world."

"Since the 1985 survey, the annual average temperatures in the region have increased by around one degree Fahrenheit," Freeman added. As a result, he says that more than two-thirds of the species studied in the research have shifted their ranges upslope an average of 40 metres to stay within their habitat.

The work in Peru follows research by Freeman that found 70 per cent of bird species on a New Guinea mountain had shifted their ranges upslope, and his team’s global meta reviews of previous studies. With Earth's average temperatures predicted to warm as much as two Celsius by 2100, tropical species can be expected to shift upslope by another 500 to 900 metres.

"Tropical mountains harbour thousands of bird species, more than any other terrestrial environment on Earth," Freeman explained. "Minimising the effects of climate change on these birds means preserving and restoring forested wildlife corridors at all elevations. Otherwise, we’ll continue to lose mountain species at this very rapid rate."

Above: Diagram illustration the upward altitudinal shift of three bird species from the study area. Common Scale-backed Antbird, a low-elevation species, has benefited from climatic warming, expanding upslope to occupy a 17 per cent larger area in 2017 than in 1975. However, the range of Veriscoloured Barbet has shrunk by two thirds and Variable Antshrike, which occupied the mountaintops in 1975, has disappeared from the region altogether. Adapted from Freeman et al.

Four more Hen Harriers disappear on Scottish grouse moors

RSPB Scotland is appealing for information following the suspicious disappearance of four satellite-tagged Hen Harriers over the past 10 weeks.

All of the birds were tagged at various nest sites, three this summer and one in 2017, in Scotland and Northern England as part of the RSPB's EU-funded Hen Harrier LIFE project. The last known locations of all four birds were over land managed for grouse shooting.

Satellite tagging technology is increasingly being used to follow the movements of birds of prey, allowing scientists to identify areas important for their feeding, roosting and nesting. The tags are fitted by licensed, trained fieldworkers and are designed to transmit regularly, even after a bird has died. In all four cases, the tags had been functioning without any issues before they suddenly and unexpectedly stopped transmitting, suggesting criminal interference has taken place.

The first bird to disappear, Athena, was one of a small number of chicks to fledge from a nest in Northumberland. She travelled north into Scotland, with her last known position on a grouse moor a few miles north west of Grantown-on-Spey, Inverness-shire, on 16 August.

Two of the birds were tagged on the National Trust for Scotland's Mar Lodge Estate in Aberdeenshire this summer. Margot disappeared on 29 August, with her last known position on a grouse moor on the Aberdeenshire/Moray border, a few miles south west of the Lecht ski centre. Stelmaria was last recorded on grouse moor a few miles north west of Ballater, Aberdeenshire on 3 September. Stelmaria's mother was DeeCee, a Hen Harrier tagged by the project in Perthshire in 2016.

Margot the Hen Harrier (RSPB).

The fourth missing bird, Heather, was a year older than the others. She was tagged at a nest in Perthshire in 2017, and last recorded on a grouse moor to the north of Glenalmond on 24 September.

Dr Cathleen Thomas, Project Manager for the RSPB's Hen Harrier LIFE project, said: "To have more Hen Harriers disappear, including three of this year's youngsters, is devastating for all of us involved in monitoring these Hen Harrier chicks. These birds have vanished in similar suspicious circumstances to four other birds tagged by the project that disappeared this summer with last recorded locations on or near grouse moors in England and Wales. These eight suspicious disappearances in the past 10 weeks are a further blow for the conservation of a species whose UK population has declined by 24 per cent since 2004.

"The main factor limiting the Hen Harrier population in the UK is illegal killing associated with intensive management of driven grouse moors. Young Hen Harrier chicks already face huge survival challenges in their first few years of life without the added threat of illegal persecution."

Heather the Hen Harrier at the nest in 2017. Her satellite tag is very evident (RSPB).

Each year a number of the chicks tagged by the project are lost through natural predation or starvation. So far in 2018 the remains of 12 young Hen Harriers have been recovered. Their tags continued to transmit after they died allowing their remains to be located and for post-mortems to take place. These established that they all died of natural causes.

Ian Thomson, Head of Investigations for RSPB Scotland, said: "Given the tiny number of Hen Harrier chicks tagged each year, the regularity with which they disappear, again indicates that we are only ever aware of a tiny proportion of the true number of protected raptors that are being illegally killed.

"In common with so many previous disappearances of satellite-tagged birds of prey, each of these missing birds was last known to be on a moor managed for driven grouse shooting before its transmitter suddenly stopped. The picture is becoming ever more clear – in almost all cases when a tagged birds dies naturally we are able to recover its remains; if it disappears over a Scottish grouse moor, it's never seen or heard of again."

Information about the birds' disappearances were passed to Police Scotland, and while local enquiries have taken place in each case, no further information on what has happened to the birds has been found. Anyone who can provide information about any of these missing birds is asked to contact Police Scotland on 101 or the RSPB's raptor crime hotline on 0300 999 0101.