Seasonal Update (February 2021)

Flooding at a nature reserve in Hampshire during the winter of 2020/21. - Credit: Marc Baldwin

Once storm “Bella” passed over on Boxing Day, the new year started on a cold but largely settled note, courtesy of an area of high pressure over Greenland pulling down Arctic air across the whole of the UK. Snow fell widely with some sizeable accumulations even at lower levels. New Year's Day saw some of the coldest temperatures of the winter; even here on the south coast we saw overnight lows of -5C (23F) with a widespread hoar frost.

At the start of the first full week of January an area of rain, sleet and snow pushed south, keeping temperatures low, although there was a milder sector over south-east England that brought daytime temperatures up to 6C (43F) and overnight lows of 3C (37F) for a couple of days. It didn't feel any warmer, though, thanks to the strong north-easterly wind and wintry (mostly rain) showers across the south-east. Wednesday night saw temperatures fall away rapidly in the west, with Wales and parts of northern England reaching overnight lows of -9C (16F) and temperatures struggling to rise above freezing during Thursday. Friday was another cold and misty day for all but the far north-west, as a weather front started pushing in from the Atlantic bringing milder air. Indeed, the second weekend was slightly milder for most by day as the Atlantic influence gradually took hold.

Most of the UK saw snowfall during January. Even some parts of the south coast had a dusting, accompanied by thunder. - Credit: Marc Baldwin

The first couple of weeks of 2021 saw extremes elsewhere, too. Northern Ireland woke up to -10C (14F) on morning of 9th January, the coldest overnight low for a decade. Spain drafted in the army to help rescue people following unprecedented snowfalls brought by storm “Filomena”. Madrid was one of the worst affected areas, receiving 20cm (8 in.) of snow and temperatures down to -12C (10F). Madrid is the highest capital city in Europe at 600m above sea level, but the average low for January is 2.7C (37F) with an average precipitation of 3.3cm (1.3 in.).

Week three was a stark contrast as a west-based North Atlantic Oscillation pumped air up from the Azores, lifting temperatures into double digits by Wednesday. At the same time a deep cold pool developed over Siberia and northern Russia, and there was much meteorological speculation about potentially tapping into that and seeing the winds change to easterlies. The north of the UK did catch some of this, but it didn’t extend far south. At dawn on Wednesday (13th) morning there was a marked temperature spread across the country - 10C (50F) in Plymouth in the rain under the mild Atlantic influence vs. -3C (27F) in Glasgow courtesy of a north-easterly airflow. The Central Highlands into Northern England saw up to 20cm of snow overnight Wednesday into Thursday, and although the mild air spread north on Thursday and Friday, it didn't push the cold air far - broadly the west of the UK was under the mild Atlantic influence, while the east, from East Anglia northwards, remained under Artic influence. The result was some snow and ice quite widely in the north and east as the leading edge of the Atlantic front met the Arctic air.

Temperatures were down again for the middle weekend of the month and the Sunday was dry, sunny and chilly pretty much UK-wide. It didn't last for England and Wales, though, and the first half of the fourth week was very unsettled, a large low pressure system bringing extremely mild (12C/54F) Atlantic air back in with accompanying rain and strong winds (50 mph) across most of England. The system, the third named storm (“Christoph”) of the season, hit parts of Wales and north-west England hardest, depositing two months worth of rain in less than 24 hours. The River Mersey at Didsbury reached its highest level on record. Christoph spun off into the northern North Sea on Thursday, allowing the Arctic influence to begin pushing back south. Thursday night and Friday were back down to the seasonal average and dropped further, down to 4C (39F) on the south coast, by Sunday. The penultimate weekend saw widespread snow even at low levels, and a single rumble of “thundersnow” here in Southampton early on Sunday.

The final week of January started on a cold note, with Katesbridge in Northern Ireland waking up to -10C on the Monday, although daytime temperatures picked up to around the seasonal average of 5-7C (41-45F) during the day. A final cold night before another low pressure system moved in from the Atlantic, bringing yet more mild wet and windy weather on Tuesday. Indeed, while it remained cold in the north we were widely into double digits in southern and central England, Wales and Ireland. Wednesday night into Thursday saw a balmy low of 10C, while London hit a remarkable 14C (57F) on Thursday.

Despite some very cold weather, January was punctuated by several very mild periods, with temperatures reaching 14C in the south. This mild weather triggered many frogs to spawn. In our garden in Southampton we had up to seven frogs in and around our tiny pond, including one pair in amplexus, when overnight lows only fell to 10C. - Credit: Marc Baldwin

As seemed to have become the pattern for January, a few days of extremely mild weather was followed by a brief switch back to an Arctic airflow for the final weekend. Temperatures were back down to around the seasonal average, or slightly below, for a day or two before we did it all over again with temperatures up at 12C to start February.

Website news

Most of my attention this month has been focussed on the research for the water deer article, which is progressing at a reasonable pace. I nonetheless managed to put together a new Speed Read section covering the basics of wild boar natural history.

In the news

Some of the nature and conservation stories that have caught my attention over the past few weeks include Met Office stats, the discovery of a new species of whale, and new proposals for grey squirrel control.

New research has identified the genetic mutation responsible for all blue eyes found in humans today. - Credit: Marc Baldwin
  • Another remarkable year. Early last month, the Met Office published their 2020 round-up, confirming what many climatologists suspected: that 2020 was the third warmest year on record (dating back to 1884), beaten only marginally by 2014 and 2006. The mean temperature for England was nearly a degree Celsius warmer than average, with 12% more rainfall and 13% more sunshine. For the UK as a whole, December proved a particularly wet month, with 135% the average rainfall.
  • Warmer waters = weaker sharks? Warming oceans have been a concern for marine biologists for more than a decade now, although only recently have we started to understand how different species are affected. New research from biologists at the New England Aquarium in Boston suggests that as sea temperatures rise, sharks hatch earlier but are weaker, making them less efficient predators.
  • Whale of a discovery. In some rare conservation good news, during November last year a team of researchers working with Sea Shepherd spotted three Perrin's beaked whales (Mesoplodon perrini) just north of Mexico’s San Benito islands. These whales are rare enough in their own right, but when the biologists analysed the acoustic recordings they collected, they noticed that they were different from those normally made by this species. It appears that they have discovered a new species of beaked whale.
  • Blue-eyed beginning. New research by the University of Copenhagen found evidence for a genetic mutation that happened between 6,000 and 10,000 years ago and caused the eye colour of all blue-eyed humans on Earth today.
  • Birth control for squirrels. Last month, the Environment Minister Lord Goldsmith confirmed that the government supports plans by DEFRA and the UK Squirrel Accord to administer contraceptive treatments to Grey squirrels in England. The announcement follows successful trials by the Squirrel Accord administering dyed hazelnut paste in place of contraceptives at feeders that suggest more than 90% of squirrels within a population could be targeted by this method.

Discoveries of the Month

Build back beaver

Familiar to many of us as the accommodating animals who take in Peter, Susan, Edmund and Lucy Pevensie in C.S. Lewis' timeless classic The Lion, the Witch and the Wardrobe, published in 1950, the beaver was once a common and widespread animal in Britain. Centuries of persecution for fur, castoreum (an oil used in perfumes, medicines, foods and even to help flavour tobacco), meat (Catholics classified them as “fish”, allowing them to be eaten on holy days) and competition with farmers for land resulted in the beaver's extinction throughout Britain and much of Europe. The last confirmed record of a beaver in Britain was one killed for a tuppence bounty along the River Wharfe in south-west York during 1789. Now, thanks to a mix of dedicated conservation projects and illegal releases, beavers are starting to recolonise parts of the UK, with populations increasing in Scotland and south-west England.

A big part of any conservation or rewilding scheme these days is convincing stakeholders that they have something to gain by, or at the very least nothing to lose from, supporting it. Beaver reintroduction plans are hugely controversial because of the extent to which these complex ecosystem engineers modify their habitat, resulting the flooding of large areas that might otherwise be used for farming. There is also still a widespread belief that beavers detrimentally affect fish stocks, despite the lack of supporting evidence. In order to placate landowners, ecologists frequently look for functions and products conveyed by their target species that are beneficial to humans. One way of approaching this is to use what we call a Millennium Ecosystem Assessment, or MEA, which divides the “services” into four categories according to their functions and benefits: regulating, provisioning, supporting, and cultural.

Beavers provide a range of ecological services, some of which are important to human society and worth tens of millions of dollars. - Credit: Helen Haden (CC BY-NC 2.0)

Stella Thompson and colleagues at the University of Helsinki conducted a large scale assessment to understand the services and products that beavers provide in the Northern Hemisphere, covering the work of both the North American (Castor canadensis) and Eurasian species (Castor fiber). The researchers identified nine services provided by beavers spanning all four of the MEA categories. Two of the “services”, nutrient cycling and historical value, couldn’t be ascribed a service value and were excluded from the final analysis, leaving: Moderation of extreme events (floods/droughts); Regulating greenhouse gas sequestration; Regulating water quality/purification; Regulating water supply; Provisioning recreational hunting and fishing; Provisioning habitat and biodiversity; and Supporting non-consumptive recreation (i.e. ecotourism).

Based on a comprehensive literature review of 119 reports across 14 countries, the researchers standardised price values for the above beaver-supplied services from various countries and years and subjected them to a meta-analysis. The striking finding was that each service evaluated was worth millions (sometimes hundreds of millions) of US dollars per year. Habitat and biodiversity provision was worth $133 million (£97m / €110m) and greenhouse gas sequestration saved $75 million (£55m / €62m), making them particularly valuable services, while ecotourism had an estimated worth of $167 per hectare (£122 / €138) and habitat and biodiversity provision an estimated $133 per hectare (£97 / €110) of beaver habitat. Writing in the Mammal Review last month, Thompson and her team advocate the implementation of a payment scheme to offset so-called “disservices” (i.e. damage) caused by beavers:

Tools are needed to ensure landowners gain more than they lose from beaver conservation. Including numerous stakeholder opinions is obviously a complex procedure, but it is possible, if, e.g., Payment for Ecosystem Services schemes are introduced. This could enable stakeholders  downstream of a dam or flood zone to compensate landowners at the flood site for benefits gained downstream, while simultaneously offsetting any damages accrued to landowners.”

Reference: Thompson, S. et al. (2021). Ecosystem services provided by beavers Castor spp. Mamm. Rev. 51: 25-39. doi: 10.1111/mam.12220.

Venturesome vulpines?

As human populations continue to expand, wild animals are faced with a choice: leave or adapt. For many species, option one is the only choice because the disturbance we create is either too great or the changes we make render the habitat uninhabitable for them. Upping sticks and moving somewhere else is fraught with danger and uncertainty, however, particularly in a world where wild spaces are under more pressure than ever before from recreational users and development. Option two, sticking it out and learning to live with your human neighbours, is a route that many species have taken. A significant problem, though, is that our tolerance of other species is notoriously fickle and we have an almost universal tendency to overlay our human values and expectations on wildlife, taking a dim view of those species with the audacity to not conform.

Foxes are a familiar sight in many towns and cities, but as generations have grown up around us many now show characteristics we'd consider bold and this has raised concerns about whether this means urban foxes are becoming dangerous. The evidence to-date suggests this is not the case. - Credit: Jess C (CC BY-NC 2.0)

The problem with a tendency towards expecting certain behaviour from wildlife is that the adage “familiarity breeds contempt” can apply in equal measure to wildlife and humans. Generations of a species having grown up around humans and having learned that they pose relatively little threat and can even be beneficial may lead to behaviour that we may consider excessively bold. Foxes provide a common example of this. Having been resident in our towns and cities since at least the 1940s, these now cosmopolitan canids are quite at home in the urban landscape. While maybe 20 or 30 years ago you may have seen only a fleeting glimpse of a fox running in the opposite direction, these days it’s not uncommon for foxes to be relaxed around people, failing to run away when approached (albeit not too closely) and even following people, particularly dogwalkers, in the street. Such behaviour prompts concern not just here in the UK but in cities across the world that foxes are becoming bolder and, in turn, pose an increasing threat.

While boldness and risk are not necessarily linked - a dog running up to you in the park may not be planning to bite you any more than a robin taking mealworms from your hand poses a threat - it is helpful to understand what affects risk-taking and neophobia, or how likely an animal is to investigate something new in its surroundings, particularly among urban carnivores such as foxes. In a recent analysis of six urban fox groups living in north-west Bristol, Roberto Padovani and his colleagues at the city’s university investigated how likely individuals were to approach a garden ornament with spinning balls that reflected light. Foxes were scored according to their reaction: neophobic (avoided completely); wariness (made a cautious approach to investigate); or boldness (unconcerned).

The data from the study, covering just over 2,100 observations and published in the journal Ecology and Evolution last month, revealed an interesting relationship between social status and wariness among these foxes. Boldness was inversely related to social status but positively correlated with social context. In other words, dominant foxes appeared more neophobic/wary than subordinates, but were generally less cautious while foraging with other foxes. Writing in the paper, the researchers conclude:

The exploratory and risk-taking behavior of subordinate foxes probably also explains why they are easier to trap, their extraterritorial mating strategies, and why they live significantly shorter lives than dominants. … While we were unable to establish the rank order of subordinates, it seems probable that particularly bold foxes are the lower ranking members of a social group.”

Padovani and his colleagues go on to suggest that their findings should be taken into account when looking at “interventions” that involve culling, because this disrupts social group cohesion and may result in an increase in the number of human-fox interactions if it promotes these less wary subordinates.

Reference: Padovani, R. et al. (2021). Are British urban foxes (Vulpes vulpes) “bold”? The importance of understanding human–wildlife interactions in urban areas. Ecol. Evol. 11: 835-851. doi: 10.1002/ece3.7087.

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