Happy New Year, to all my readers. I hope your festive season was the best it could be, and that 2024 is good one for you and your family. A quick reminder, too, as we approach a couple of weeks of people reminiscing on their accomplishments over the past year, it's perfectly okay if all you did last year was make it into this one.
I've been rather remiss when it comes to providing new content on the website in recent months, and I'm sorry for that. I am approaching what I feel is the “end” of writing the water deer article, after which I intend to devote some significant time to reviewing, revising, and revamping the existing species profiles. Last month, however, a new section of the water deer article, covering maturity and dispersal, went live, and more on the territorial behaviour will follow this month.
December started on an unseasonably cold note across the UK, with even Heathrow failing to climb above zero Celsius (32F) on 2nd December. The cold snap was short-lived for most of England, however, and December was another unusually mild month. Temperatures were widely into double figures by the second weekend, with the south coast reaching 14C (57F) on the 9th, which is remarkably temperate for the time of year. The same weekend saw storms “Elin” and “Fergus” move through, bringing strong winds and heavy rain, causing some localised flooding and power cuts.
For most of the month, much of the UK was bathed in air pulled up from the Azores, the high centred over France and Spain, and even Scotland and Northern Ireland saw overnight lows of 11C (52F) and daytime highs of 13 or 14C (55-57F). Here on the south coast, despite a brief drop in temperatures for one night in the week preceding Christmas, temperatures hung around 12C by day and night. Just ahead of the Christmas weekend storm “Pia” brought severe gales to the parts of Scotland, and a yellow warning for wind that extended as far south as Suffolk. Christmas Eve was surprisingly mild in England, with Heathrow reaching 15.3C (59.5F), and with a wind that felt almost warm. It was also the warmest Christmas Day on record for England, with parts of the south registering overnight lows of 12.4C (54F). It's worth noting that it's not uncommon or necessarily unexpected for it to be mild around Christmas in the south of England during an El Niño year, but this Christmas is especially mild for most of England as we'd normally expect highs of about 8C by day and 4C overnight.
Christmas itself was colder in the north, but mild and wet in the south, the rain on and off through Christmas Day, but drier, brighter and cooler for most of Boxing Day. Christmas week was a wet and very windy affair across the UK. Storm “Gerrit” brought damaging winds and heavy rain that caused widespread flooding on the 27th. Wind gusts were widely around 60 mph (96 kph), but in excess of 80 mph in Scotland and parts of northern England and Wales. Anglesey, for example, recorded 88 mph and the Fair Isle 89 mph (143 kph), while a suspected tornado caused significant damage in Greater Manchester. The remainder of Christmas week a mix of showers and strong gusty winds, with another low arriving for the final weekend that brought yet more heavy and persistent rain.
Outside of the UK, Morocco saw exceptional heat with temperatures above 30C (86F) in the south at Essaouira Airport, and uncommonly warm also in the highlands. Record heat for December was also recorded at Ouarzazate with 27.2C (81F). Southwest Europe and Morocco were also subject to early winter warmth, with overnight lows of 17C (63F) in northern Spain and Portugal during the second weekend. Santa Maria fell to only 19.2C (66.6F), the highest December low so far recorded in the Azores, 29C (84F) in the Canary Islands and an exceptional 33C (91F) in Essaouira, Morocco. Tokyo was also warm last month, with some tropical nights reported, including 21.5C (70.7F) at Miyake and 20.9C (69.6F) at Nijima. China, by contrast, saw extreme cold, with -33.2C (-27.8F) recorded at Yunzhou and -29.7C (-21.5F) at Qingshuihe. The Greenland Summit Camp Station also cooled sharply in late December and by Christmas night it bottomed at -59.8C (-75.6F), overtaking Siberia as the lowest temperature so far in Northern Hemisphere this season.
News and discoveries
Savvy spiders. Recognition of individuals is thought to be an important element of sociality in animals, although it's an area that has received relatively little study outside of mammals. A recent study awaiting publication suggests, however, that some spiders may have short-term memory of spiders they've seen before. Scientists tested the ability of regal jumping spiders (Phidippus regius) to remember other individuals that they'd encountered in a previous experiment and found that spiders tended to stay further away from others they'd met previously, whereas they readily approached strangers. This recollection seemed only short-term, fading after about an hour.
Total recall. Not to be outdone by the arachnids, chimps and bonobos have also recently been shown to have excellent memories for individuals they've encountered before - even two decades later. New data published in the Proceedings of the National Academy of Sciences suggest that not only do these primates remember others over long periods, but they also seem to recall whether past interactions have been positive. The apes were bribed into taking part in the experiments with juice and while they sipped, they were shown photographs of animals they'd encountered previously. The participants spent longer looking photos of primates they'd seen before and responded more enthusiastically to those they'd had positive experiences with previously. In one extreme case, over eight trials a bonobo showed a striking looking bias at photos of her sister and nephew that she hadn't seen for more than 26 years.
Ecological cat-astrophe. A recent survey suggests that nearly one in four adults in the UK have a cat, putting Britain's estimated population at some 11 million felines. As most are aware, while cats can make wonderful companions, they can also have a significant impact on wildlife and few cat owners have never had to face removing a “gift” of a dead something-or-other from the house. Scientists at Auburn University in Alabama recently undertook the unenviable task of trying to catalogue the total number of species taken by domestic cats. The list, published in Nature Communications contains 2,084 species, 347 of which are of conservation concern.
Seasonal highlight – The European robin (Erithacus rubecula)
The results from the RSPB's Big Garden Bird Watch carried out last winter showed that robins were the eighth most frequently garden-recorded bird; the average garden playing host to 1.3 birds. Indeed, robins are the garden birds that pretty much everyone can identify, and this enigmatic bird has held the title of Britain's national bird since 15th December 1960, following a long correspondence on the subject in The Times newspaper.
The robin goes by many names: Bobby (here in New Forest, Hampshire); Ploughman's bird (Yorkshire); reddock (Dorset); and ruddock (northern England) to name a few. Ruddock appears to have been the first name for this bird in the literature, appearing early in the 12th Century and derived from the Old English ruddy, meaning 'red'. (Orange, as a word, didn't appear in the English language until the 14th Century.) Redbreast as a name for the robin appeared towards the end of the 14th Century, with the popular Christian name Robin appended during the mid-16th Century. The name 'Cock Robin', according to Stefan Buczacki's Fauna Britannica, can be traced back some 300 years and indicates that this little bird was a familiar sight by then.
For centuries the robin has been deeply rooted in our culture and religion; one Just So story on the origin of the red breast is that the bird became stained with Christ's blood as it ministered to him on the way to Calvary. The first Christmas card was designed by John Horsley and sent by wealthy British businessman Sir Henry Cole in 1843 and, since then, the robin has appeared on millions of these cards. Victorian postmen were nicknamed 'robins' because they wore red and delivered Christmas cards on Christmas morning. Consequently, Victorian Christmas cards often depicted robins delivering Christmas post. This Victorian notion stuck, and robins still feature on Christmas cards today. Robins are also close to the heart of many gardeners and those turning soil this winter are almost guaranteed to attract the attention of a robin, keen to pick off any invertebrates exposed in the process. For me, robins were also one of my first animal behaviour studies, involving estimating territory size, while I was studying at the University of Essex. How much, however, do we really know about this most familiar of garden visitors?
Linnaeus' red breasted tail-mover
Carl von Linné was the first to formally describe and classify the robin in his 1758 Systema Naturae, in which he named it Motacilla rubecula. The genus Motacilla comes from the Latin meaning 'tail mover' and is now reserved for the wagtails. Not everybody agreed with Linnaeus that robins were most closely allied with the wagtails and some four decades later, in 1800, French naturalist Georges Cuvier published the first volume of his Leçons d'anatomie comparée (Lessons from Comparative Anatomy). In this volume, Cuvier reassessed the anatomy of the robin and considered it sufficiently distinct to warrant reclassification, distinct from the other tail movers. Consequently, Cuvier created the genus Erithacus (from the Greek erithakos, meaning 'solitary') and here the robin sits today, with its currently accepted scientific name, Erithacus rubecula (rubecula from the Latin ruber, meaning 'red'). The species does vary slightly across its range, where it is sometimes divided into as many as nine subspecies; the subspecies common to the UK and Ireland is Erithacus rubecula melophilus, meaning 'lover of song' (from the Greek melos, 'song', and phileo, 'to love'). At this point, it is worth mentioning that the larger American robin (Turdus migratorius) is named for its similarity to the European robin but is not closely related to our redbreast.
So, what is a robin? Robins are insectivorous (insect-eating, favouring caterpillars, spiders, small flies, etc.) birds common in deciduous and mixed woodland, open parkland, mixed farmland, and gardens of all sizes where feeding opportunities exist. Robins are small birds; adults stand 12 to 14 cm (5-5.5 in.) tall, have a wingspan of about 21 cm (8.5 in.), and weigh in at 16 to 22 grams (0.5-0.78 oz.). Adult birds sport a buff brown/grey cap and back plumage, with striking orange face, 'cheeks' and breast plumage that highlight a pair of small, round black eyes. The orange plumage is the result of diet-derived carotenoid pigments laid down in the feathers and its extent varies slightly with individuals, but typically extends no further down than the 'waist' of the bird; the remaining underside is off-white or pale grey in colour. Robins have reddish-pink legs.
The sexes are largely indistinguishable, although males and females do apparently vary in the shape of the boundary between the orange and grey plumage on the brow. Indeed, in 2011, a team of Spanish researchers studying robins in pine plantation in Barcelona reported that the size of the orange breast and grey fringe bordering the breast on three sides varied according to age and sex of the bird. The biologists also noted how the grey fringe appeared to draw attention to the red in poor light, probably to make it more noticeable to potential rivals.
The when, where, and how
European robins are widespread across Europe and Asia, from the UK and Ireland east to western Siberia and south to Algeria, with birds found on Atlantic Islands as far west as Madeira. Within Europe the breeding population is huge, some estimates suggesting more than 43 million pairs. In the UK, there is fossil evidence placing robins here back during the last (Devensian) glaciations some 10,000 to 120,000 years ago. In 2009, the RSPB estimated that Britain held almost six million robin territories and, each winter, our resident birds are joined by individuals from Scandinavia and Russia, recognised by their duller orange plumage. On average, these birds live for just over a year, owing to high juvenile mortality. If a bird makes it to its second birthday life expectancy is greater, increasing to an average of five years, with the oldest ringed bird (tagged in 1977) reaching almost eight and a half years old.
Despite their demure appearance, robins are territorial birds and can be highly aggressive and an estimated 10% of birds are killed each year in fights with other robins. Male birds maintain the same territory throughout the year, while females tend to have separate nesting (summer) and feeding (winter) territories. Territories are marked by singing and posturing to rivals; if this fails to dissuade intruders fighting may ensue, following highly stereotyped behaviours.
Robins sing throughout the year, except in late summer when they're moulting, with the spring (breeding) song being louder and more forceful than the more melancholy autumn song. In urban areas there has been a relatively recent increase in nighttime singing, which we think reflects the daytime noise of the city (i.e., it's quieter at night, so it's easier for them to make themselves heard). Indeed, a recent study by researchers at Sheffield University found that daytime noise was a better predictor of nocturnal singing in robins than artificial light intensity, suggesting that it's not the light pollution in urban areas tricking the birds into thinking it's dawn. Similarly, earlier this year, researchers at Queens University Belfast found that, as noise levels increased, male robins were more likely to move away and change their songs, the louder the noise, the less complex the robin's song. So, living in towns affects the singing behaviour, both its timing and how elaborate the song is, of our redbreasts.
If singing doesn't dissuade an intruder from entering the territory, and the two birds meet, a fight may ensue. The resident bird will begin by ruffling its feathers, craning its head, and dropping its wings, before striking at the intruder with single blows from the feet and wings. If the intruder doesn't back down, both birds may roll around kicking and wing-beating each other, and jumping/fluttering up in front of each other, striking out with their feet. Each bird attempts to pin its rival to the ground in what may be a prolonged and violent clash - fights have been recorded to last anywhere from a few seconds to well over an hour.
A great deal of what we know about the territoriality and fight triggers of the robin comes from the meticulous work of the late London-born evolutionary biologist David Lack, much of which was published in his seminal 50-page paper to the Proceedings of the Zoological Society in 1939 and subsequently in his first book, The Life of the Robin, in 1943. Lack studied robins in Devon between 1934 and 1938 and observed that each breeding pair had a territory of between 0.17 and 0.84 hectares (0.4 to 2 acres) in size; the unshared autumn territory varied between and 0.07 and 0.5 ha (0.17 and 1.3 acres). In other words, during the breeding season there was a robin per one to six hectares (2.5 to 15 acres). These territories were defended from intruders, although each robin frequently trespassed while feeding. Lack noticed that the robins would chase any flying birds passing through their territory, whether they sported a red breast or not (wrens being frequently targeted and juvenile robins were sometimes attacked), and he could elicit attack behaviour using models with and without the red breast.
Generally, Lack found that there were usually specific triggers for specific actions: a bird flying away would elicit a chase; a song would trigger a response song; a robin-shaped model would elicit an attack; and a red breast (whether on a robin or not) would cause posturing by the territory holder. These triggers weren't absolute, however, and a territory holder would sometimes sing at a silent robin, strike at a red breast, etc. Robins were only triggered to attack while on their territory; the trigger to attack was not simply any other robin, but another robin (excluding their mate, which males seemed to recognise individually) within a specific area. Again, this observation was not absolute and Lack did record that, on occasion, a male without a territory would attack and evict a territory holder. Lack noted that, when posturing, the position of the red breast is relative to the position of the intruder so that the largest possible area of orange is displayed. The aim of all this aggression is to secure a territory that will both attract a female and provide sufficient food resources to raise a brood of chicks.
Robins pair up between mid-December and mid-March, with nest-building towards the end of March. Nests take the form of a neat cup—composed of moss, leaves, and grass, with finer grass, hair and feathers used as lining—built in a hole or on the ground. The first copulations usually occur during April, although there are records as early as January, shortly after which the female will lay five to seven eggs that can be cream, buff, or speckled white (blotched with reddish-brown) in colour. Incubation lasts 11 to 14 days and during this time the female is fed by the male, typically every 20 minutes or so. The chicks are fed by both parents and fledge about two weeks after hatching, at which point they have their juvenile brown plumage with pale spots - orange patches appear as the bird begins to moult.
Juveniles are independent at about three weeks old and become sexually mature at about a year old. The female will lay a succession of broods, usually amounting to two or three clutches, until around June, when breeding activity stops and the birds begin to moult.
I hope this brief diversion into the world of the robin has convinced you that there is more to these endearing little garden birds than meets the eye. Keep an eye out for robin activity in your garden, local wood, park, or allotment this winter and please get in touch with any interesting observations or photos. Also, remember that the RSPB's Big Garden Birdwatch is running from the 26th to 28th January, and you can sign up to take part on their website.
For a round-up of Britain's seasonal wildlife highlights for mid-winter, check out my Wildlife Watching - January blog.