Seasonal Update (March 2022)

Storm Eunice hit the UK towards the end of February bringing damaging winds. Many coastal areas were badly hit, including the Isle of Wight, The Needles recording 125.4 mph winds. - Credit: Paul Blackley

Named storms were a feature of last month. Following a tumultuous weekend for Scotland and northern England to see out January, courtesy of storms Malik and Corrie, February started on a more settled note for most, but remained unseasonably mild. Strong winds held on in the far north for the start of the first week, but it was mild across the board with highs of 11C (52F) in the north and 14C (57F) in the south-east. This mild airflow hung around for a few days in the south before temperatures very briefly dipped back down into single figures on the first Friday.

The second week of February brought fluctuating temperatures and significant contrasts between the north and south, much as January had done. After a wet, windy and mild end to the first weekend in the south, parts of Scotland and northern England saw snow, even at lower levels. The south of England saw a brief dip in temperatures to the seasonal average on Monday before climbing to highs of 14C and overnight lows of 12C (54F), falling off again towards the end of the week. Scotland saw rain, snow and strong winds through the first half of week two. Cooler and more settled conditions prevailed into the second weekend.

The middle week was unsettled, but again very mild. In England, alongside rain and strong winds, temperatures hit highs of 17C (63F) in the south-east, which is remarkably mild for mid-February. The main weather news was towards the end of the month, however, with the arrival of three named storms in rapid succession.

Storm Dudley was the first to arrive and brought winds of 80-90 mph (129-145 kph) across northern England and southern Scotland. Many trees were blown down and thousands of homes were left without power. The accompanying heavy rain meant that many areas also flooded. Aonoch Mor near Ben Nevis in Scotland recorded 101mph (162.5 kph) winds as Dudley swept through.

Three consecutive powerful storms resulted in a great many trees coming down across the UK. - Credit: Marc Baldwin

Next in line was a very deep area of low pressure named Storm Eunice by the Met Office. This storm was one of the worst the UK had seen for at least 15 years and may even have surpassed the infamous storm of '87. There were inland gusts widely of 80 mph, with 90-100 mph on the south coast on Friday 19th. Indeed, we saw 92 mph (151 kmph) recorded at Southampton Docks and 124.5 mph (200 kmph) at The Needles on the Isle of Wight, the latter of which appears to be an English windspeed record. Tragically, three people were killed by falling trees/debris. There were several injuries reported, numerous trees down and a staggering 400,000 homes without power, some of which weren't reconnected for six days. Eunice triggered the Met Office to issue a rare red warning in south-west England and southern Wales and its first ever red warning for the south-east - red warnings signify a danger to life.

Eunice moved away early on Saturday morning and was swiftly followed by another low: Storm Franklin. Franklin was a huge area of low pressure that brought 60 mph (96 kph) winds across Ireland and England, with 80 mph gusts in Northern Ireland, north Wales, northern England and parts of the Midlands on Sunday (20th) night and Monday morning - The Needles recorded 87 mph (147 kph) winds. An amber warning for wind was issued for eastern Northern Ireland, with a yellow warning for Wales, England, and south-west Scotland. Unlike Eunice, Franklin also brought some heavy rain. Indeed, both East and West Didsbury in Manchester were put under the highest flood alert after the River Mersey burst its banks, with some 450 residents told to evacuate their homes as the floodwater posed a danger to life. The River Severn in Shropshire also burst its banks, causing widespread flooding.

Outside of the UK, early February was harshly wintery in most of USA, bar the south-east where 27C (80F) was reached in the Carolinas. Most of Texas saw freezing conditions, with extremes ranging from a low of -44C (-48F) at Antero Reservoir in Colorado to 31C (88F) at Plant City in Florida. Brazil had a month's worth of rain in about 48 hours during the middle of last month, causing mudslides that claimed 94 lives.

The spring/summer song of the blackbird can be heard during March and gives a real sense that warmer weather is on the way. - Credit: Marc Baldwin

If you're interested in getting out and about this month to look for wildlife, check out my March wildlife overview. Additionally, the British Deer Society are running their Deer Distribution Survey and I would strongly encourage readers to record their sightings of wild deer either via the app or by e-mailing the Society directly. Citizen Science such as this helps get a clearer picture of deer populations around the country, helping improve their management.

In the news

A few of the stories that caught my interest over the last few weeks include how air pollution makes it harder for insects to find plants, altruistic magpies and apparent tool use by bees:

A recent study by biologists in Cardiff suggests that many otters have bioaccumulated "forever chemicals" from non-stick coatings and waterproof clothing. - Credit: Marc Baldwin
  • Pollinators vs. pollution. The results of a new study by UK-based scientists has revealed how common air pollutants, such as nitrogen oxide and ozone, can react with floral odours and severely impact the foraging efficiency of pollinators. Levels of air pollution at levels around average for UK roads reduced the counts of pollinators by 70% compared to controls.
  • Otters back on the brink? Several so-called “forever chemicals”, named because they don't break down in the environment, have been found in otters across England and Wales, according to recent data from Cardiff's Otter Project. At least twelve PFAS chemicals, widely used in non-stick saucepans, food packaging and waterproof clothing, were found in the livers of 80% of the otters tested. These chemicals are well-known to cause disease in humans, including cancer and pregnancy complications.
  • Whale whoopsie. An international project is underway to find out whether humans can artificially emulate the benefits of whale poo in the hope that we can simultaneously boost fish populations in the oceans and tackle climate change.
  • Bee-ing smart? Asian honey bees have recently been observed using animal dung to repel hornets in what appears to be the first record of “tool use” in this species. Researchers in Vietnam found that hornets were less likely to hang around the hive entrance as it became covered with more dung.
  • Plastic precipitation. A study in the High Tauern National Park in Austria suggests there could be as many as 3,000 tonnes of nanoplastics rain down on Switzerland every year. According to the study, about 30% of the nanoplastic particles measured on the mountain originate from a 200 km (124 mile) radius, mainly from cities, with 10% blown in from more than 2,000 km (1,243 miles) away.
  • Matey magpies. Researchers undertaking radio-tracking Australian magpies in Queensland observed the birds cooperating to remove the devices. In a recent paper to Australian Field Ornithology, the scientists told how: “Despite previous testing demonstrating the strength and durability of the harness, devices were removed within minutes to hours of initial fitting. Notably, removal was observed to involve one bird snapping another bird's harness at the only weak point, such that the tracker was released”.

Website news

This month has mostly been tidying up a few sections on the website in preparation to introduce some updated content shortly and working on the Chinese water deer article. Part five of the article is now with the proof-readers and I have made a start on the next chapter. Two new sections have also gone live in the last week or so, covering field signs and water deer distribution.

The creation of the Chinese water deer profile is continuing and new sections are uploaded periodically. - Credit: Marc Baldwin

Discoveries of the Month

Flank to fork? The function of skin in shark feeding behaviour

We often think of sharks as being pretty hardy creatures - fish full of teeth. Not only do sharks continue to produce teeth throughout their lives, born with a conveyor belt mechanism that kicks in while they're in the womb and ensures worn and broken teeth are replaced promptly, their skin is also covered with tiny tooth-like structures known as dermal denticles - literally “skin teeth”.

These denticles vary in size, shape and orientation/arrangement across the body, but broadly point towards the tail. The result is that the shark is quite smooth if stroked tail-to-head, but the skin is very rough when rubbed the other way. Early entrepreneurial humans recognised that this roughness could be exploited, and the skin was used as handles for ceremonial weapons, providing an enhanced grip, and even as a sandpaper equivalent called “shagreen”. Initially, we thought the function of these denticles was just one of drag resistance, helping to smooth the flow of water across the skin to make the shark more aerodynamic. Indeed, in recent years, scientists have been copying the “design” and applying it to submarines and swimwear to help increase speed in the water. While improving laminar flow is clearly important, and presumably the main driver for their evolution, recent observations by marine biologists on captive sharks suggests that rough skin may have a more surprising function.

Scanning electron micrographs of the dermal denticles (skin teeth) from the Chain catshark (Scyliorhinus retifer), a relative of the small-spotted catshark. The letters represent different parts of the skin, illustrating how they rapidly change shape. - Credit: Galber-Smith et al. (2021) / Oxford Academic (CC BY)

Emily Southall and David Sims documented the feeding behaviour of small-spotted catshark (Scyliorhinus canicula) pups born and raised at the Marine Biological Association's aquarium in Plymouth. While watching back the video recordings of the sharks feeding on pieces of chopped up squid, the biologists noticed that small pieces were grabbed and shaken violently to break off a bite-size chunk, but some of the pieces were too big for this approach. When confronted with a large lump of food, the sharks of all ages consistently grabbed hold of it, snapped their head around to hit the food against the lower flank of their tail, causing it to become hooked, snapping the head back the other way even quicker. The result was that a bite-sized chunk of meat was torn off and swallowed. Southall and Sims named this behaviour “scale-rasping” and noted that its success was related to whether the food became anchored on the initial strike.

Having witnessed this curious behaviour, the researchers looked at the skin of sharks between three and seven months old under a scanning electron microscope and found that there were numerous, well-defined dermal denticles in this trunk region, each ranging from 0.4 to 0.7 mm in length. Writing in Biology Letters, Southall and Sims note:

Dermal denticles in adults protrude further from the body surface in the lateral caudal-peduncle area compared with other body areas, perhaps as a result of hydrodynamic adaptations, but the relative extension of denticles is an order of magnitude smaller in adults than in juveniles (extension from body surface was 0.02% and 0.18% of body length, respectively). This difference predicts that food anchoring should be less successful in adults and may reflect the low observed frequency. However, scale rasping may also be less common in adults (body length of ca. 0.7 m) because they are not usually gape limited with respect to preferred prey species such as small-bodied crabs and prawns.”

Reference: Southall, E.J. and Sims, D.W. (2003). Shark skin: a function in feeding. Biol. Lett. 270: S47-S49. doi: 10.1098/rsbl.2003.0006.

Doggedly in pursuit of disease

While globally considered to be of conservation “Least Concern” by the IUCN, the Red squirrel (Sciurus vulgaris) has been classified as “Endangered” in Great Britain as a whole, with only Scotland ranked as “Near Threatened”. There are a number of factors that have brought about the species' current low population level in the UK, and the introduction and spread of the Grey squirrel (S. carolinensis) from North America is one piece of the puzzle. A significant issue when it comes to the presence of the Grey is that they appear able to carry and transmit a viral parasite, squirrelpox, that can infect Red squirrels and generally proves fatal. The Greys themselves rarely seem to succumb to the British strain of the virus.

Trail-camera image of a red squirrel displaying significant skin disease from Treborth gardens, Bangor, during an outbreak of squirrelpox in 2019. - Credit: Shuttleworth et al. (2022) / Multidisciplinary Digital Publishing Institute (CC BY)

Over the past few years, proliferation of good quality trail cameras has increased the ease with which we can monitor wildlife populations, and this can help us identify disease outbreaks. More recently, effort has been directed to training dogs to sniff out a variety of species and these “wildlife detection dogs” have proven highly effective at finding animals for tagging and surveying. During a recent outbreak of squirrelpox in Wales, one such detection dog was used to help locate carcasses in dense woodland.

Craig Shuttleworth at Bangor University led a team of researchers to study an outbreak of squirrelpox on Anglesey during 2017 and 2020/21 using live trapping, trail camera monitoring and a day with a detection dog looking for carcasses. While the data collection was opportunistic in nature, the results nonetheless provide a valuable insight into the local impact of disease outbreaks in squirrel populations. The data suggest that the squirrel population underwent a significant decline in response to the infection, with perhaps as much as 86% of the population succumbing. A Belgian shepherd dog called Max was used to search a two-kilometre (1.3 miles) stretch of coastal woodland in northern Gwynedd. Max found red squirrel fur that was subsequently sent to the APHA laboratory in Surrey for analysis. In their paper to Animals, published earlier this year, Shuttleworth and his team conclude that the use of detection dogs was effective and is recommended:

The use of a conservation dog to detect red squirrel carcasses resulted in positive detection and confirmation of a temporal and spatial expansion of one disease outbreak.”

Reference: Shuttleworth, C.M. et al. (2022). An opportunistic assessment of the impact of squirrelpox disease outbreaks upon a red squirrel population sympatric with grey squirrels in Wales. Anim. 12: 99. doi: 10.3390/ani12010099.

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