Seasonal Update (October 2022)

Domestic pigs out in New Forest woodland during the pannage season. - Credit: Marc Baldwin

October, named from the from Latin and Greek ôctō meaning “eight”, is perhaps the quintessential autumn month. The arboreal colour change is in full swing, along with the deer rut and pannage, and the nights are appreciably longer and colder, bringing blankets and jumpers out of the cupboard. Nothing quite beats walking in a deciduous woodland on a cold, sunny October day, and the mix of colour and activity in the natural world makes autumn hands-down my favourite season. We're now also at the peak of decorative gourd season - Google it if you're comfortable with strong language - if you partake in such tradition.

Weather update

To say that September was a tumultuous month, weather-wise, seems to understate a month in which we saw weather records broken around the globe. In the UK, it started on a largely dry note with a few hit-and-miss showers. Indeed, much of the UK remains in drought even as I type this because, although we did see low pressure arrive during the second week that brought some heavy thundery showers in from the Atlantic, high pressure across northern Europe meant that rain struggled to make significant inroads in the south-east. The final week was also showery, with a fairly deep low pushing in on the last Friday bringing wet and windy conditions with it, but overall September was another arid month for most of England, with temperatures fluctuating around average.

A street in Collier County, Florida, flooded as Hurricane Ian battered the western coast. - Credit: Florida Fish & Wildlife (CC BY-NC-ND 2.0)

Outside of the UK, the picture of destruction caused by the devastating floods in Pakistan continued to emerge, with significant loss of life and damage to property and crops. Puerto Rico also suffered its worst flooding in history after Hurricane Fiona passed through, depositing some 75 cm (2.5 ft.) of rain in only a few hours and causing widespread destruction and power outages. Forty-one centimetres (16 in.) of rain also fell in Italy's Marche region during the middle of last month, creating flash flooding that killed at least 12 people, while southern Japan was battered by “super typhoon” “Nanmadol”, which forced the evacuation of more than eight million people. Typhoon “Noru” underwent some of the most explosive intensification ever witnessed in a tropical cyclone; after initially being predicted to hit the Philippines as a Category 2 hurricane, within a few hours it had grown to a Category 5 “super typhoon”. Similarly, hurricane “Ian” rapidly intensified in the Atlantic before battering Florida's west coast in the final week of September, bringing winds in excess of 150 mph (240 kmph) along with torrential rain and storm surges of nearly three metres (9 ft.).

Temperature records were also widely broken. Over the first weekend, British Columbia registered its hottest September day on record as Lytton reached 39.6C (103F), 0.4C (0.7F) short of the all-time Canadian September heat record. Across North America as a whole, early September saw a barrage of monthly temperature records broken across Montana, Idaho and Utah, with the most intense heat in the far west. Farfield in San Francisco Bay recorded a staggering 47.2C (117F) on 5th September, while Sacramento in California broke its all-time heat record, set in 1925, when it hit 46.7C (116F) the day after, and Death Valley recorded 51.3C (124.4F) on 1st September.

The temperature anomaly that Europe experienced towards the end of September, including some early, heavy frosts in the north and east. - Credit: WX Charts (CC BY-NC-ND 2.0)

France recorded its hottest September day on record on the 12th, with temperatures peaking at 40.7C (105F), and Greenland observed extensive melting with the largest September melt event on record after a cooler than average summer. The Summit Station in Greenland, at an elevation of more than 3,200 meters (10,500 feet), surpassed the melting point for the first time on record in September at the start of last month. Sea surface temperatures were also predominantly above average across the northern hemisphere, with the North Atlantic continuing to break temperature records last month.

While southern Europe continued to bake, we saw record cold and early frosts across most of north-east Europe, some of the Arctic air even briefly reaching the UK in late September. Chile experienced a rare historic snowfall in the city of Osorno around the middle of last month. Snow accumulation is extremely rare in Chile and almost unheard in the city centre, but several centimetres were recorded.

Website news

Some general tidying up has been done to the fox territory and hedgehog parasites and diseases sections, and the latest part of the Chinese water deer article, covering their habitat, has gone live.

News and discoveries

Waste not want not. Zoologists at Whipsnade Zoo are collecting samples of dung from their elephant herd for genotyping. Conservationists working on wild elephant populations routinely use faecal DNA testing to better understand population sizes, identify key populations, select elephants suitable for translocations, and identify where inbreeding may be an issue. Unfortunately, there's still much uncertainty about how long samples can be stored before analysis, or even which method is best for preserving the samples. By working with samples from captive elephants it is hoped the new research project will help fill these gaps.

Pine marten populations appear to be increasing in the UK, having previously been restricted to isolated populations in Scotland and Wales. Earlier this year, one was caught on a trail camera in the London borough of Kingston Upon Thames. - Credit: Caroline Legg (CC BY 2.0)

Metropolitan mustelids? Zoological Society of London biologists are used to sifting through trailcam footage of foxes, dogs, hedgehogs and even the occasional badger when checking their traps setup to monitor hedgehog populations in parts of the capital. A pine marten showing up in the borough of Kingston Upon Thames was, however, something of a surprise. The photograph, taken shortly after 1AM on 3rd July, represents the first confirmed sighting of the species in London since the early 1920s, although it remains unknown from where this individual originated, given that the closest known population is some 112 km (70 miles) away in the northern New Forest.

Spider skills. Combined, spiders contribute the most species-rich taxon of predators on earth, and they have evolved a fascinating diversity of hunting techniques, including hunting in groups, specialised silk, pheromone-loaded bolas, and even aggressive mimicry. Now, new science by a team of researchers in Germany and Australia has revealed how some species use fast, acrobatic manoeuvres to capture dangerous prey with a striking success rate. These spiders can dart in, attach silk, and jump back out of the way to then entangle their ant prey in hundredths of milliseconds.

Knock! Knock! Researchers following the Waibira chimpanzee group in western Uganda's Budongo Forest noticed something particularly curious when they analysed the drumming behaviour they observed. The drumming, which chimps make using their hands and feet, typically against tree trunks, can carry for more than a kilometre through the forest and seems to convey more than just a chimp being around. The scientists noticed that within a few weeks they could identify who was drumming from the rhythm they played out on the trees. Each chimp seemed to have their own signature beat, communicating their presence to others in the area. More interesting still was that they sometimes chose not to drum their own signature, the scientists presume, because they don't want to alert others to their location.

Revisiting rewilding. Many landowners balk at the idea of rewilding, raising concerns over livelihoods and rural society, as well as the inevitable issues associated with releasing predators into the British landscape. A recent assessment suggests, however, that agricultural rewilding, which typically involves restoring ecosystems by introducing native hardy breeds of livestock to act as analogues for their historic wild counterparts, can offer both environmental and social benefits. The report argues that, when done properly, agricultural rewilding can offer increased tree planting, habitat restoration, and improved flood management, while also generating high quality and high welfare meat that's environmentally, ethically, and financially sustainable - all while humans continue to manage the land.

Seasonal highlight – deer desires

Unquestionably, autumn is the season for deer watching, and October marks the peak of the rutting season. The relentless drive of modernity means that much in life changes at a staggering pace and, for me at least, there's something grounding about being out in woodland or on the heath as the sun starts to rise on a chilly mid-autumn morning, listening to eerie calls that a medieval peasant or knight would've recognised.

A fallow buck crosses a track on the New Forest shortly after dawn. October is the peak of the rut for four of our seven deer. - Credit: Marc Baldwin

The condition of the deer affects when they rut, and in particular how likely females are to conceive, but weather also has a significant impact on its timing. Mild and wet weather delays it, while cool and dry conditions trigger and may even advance it. It has recently been suggested that climate change is advancing the red deer breeding cycle on the island of Rum, off the coast of eastern Scotland. In 2013, Edinburgh University zoologist Dan Nussey and colleagues published data suggesting that, perhaps because of warmer springs and summers allowing for longer feeding periods, the birth of calves and the time that males start rutting is now as much as two weeks earlier than when the study began almost 40 years ago.

Another disturbing finding by the team was the amount of introgression (i.e., mixing of characteristics as a result of inter-breeding) between red and the closely-related sika deer, which roam wild in many parts of Britain. Based on data collected from Scotland's Kintyre Peninsula, it appears that red deer are getting smaller, while sika are growing larger. What it appears we're seeing is a blending of traits, providing what some consider a “mongrel” deer. Hybridisation between these species is a problem wherever they co-exist, and in many parts of the country, especially here in the New Forest in Hampshire, red and sika deer are shot if they encroach on each other's ranges in a bid to prevent such interbreeding. Problems aside, red, fallow and sika all rut in the coming weeks and each have their own rutting behaviour and unique call. Red stags (Cervus elaphus) bellow/roar/bolve, fallow bucks (Dama dama) “belch”, and sika stags (Cervus nippon) “whistle”. Well worth checking out if you have the opportunity.

A Red deer (_Cervus elaphus_) stag roaring (bolving) at Richmond Park. - Credit: Marc Baldwin

Rutting activity starts as the nights draw in and the temperature drops; this stimulates a rise in testosterone in the bucks and stags, and formerly relatively good-natured bunches of guys hanging out together start to experience conflict, leading to the breakup of bachelor groups.

Fallow bucks, being a woodland species, tend to set themselves up in a good spot and proceed to “belch” or groan, scrape the ground and nearby trees, and generally spread their scent around in an attempt to advertise their presence to any females the area. This method of mating is called lekking. Research on fallow rutting suggests that females can judge how big a male is from the acoustics of his belch. Males that belch constantly are perceived as the fittest individuals (i.e., those with the greatest stamina) and are the ones more likely to mate.

Red deer, by contrast, being a species now restricted to more open moorland/heathland habitats, are “showier” in their rutting. Red stags move to traditional rutting grounds in pursuit of the females. The females move to areas of best grazing to rebuild their fat reserves following a summer of producing milk for their calves, and the males follow. We used to think that a male rallied up a collection of hinds and held them until either they started coming into oestrous or he was deposed by another stag. Thanks to some fascinating in-depth studies conducted by the Red Deer Research Group on Rum, however, we now know the situation is much more flexible. The males do follow the females around and the largest/strongest stag tends to have unrestricted access to the largest group of hinds, roaring to advertise his prowess both to the nearby females and any stags thinking of challenging him. We now know that females may move between different harems if they're impressed by a neighbouring stag, or to get away from smaller stags pestering them. We also know that if the matriarch decides to move to another area, there is little the attending stag can do but watch his harem disappear. A female may also duck out of a harem briefly to mate with a nearby stag and return to her group afterwards.

Sika are slightly different again, tending to set up leks in areas between the feeding and resting grounds chosen by females, from which they stand and whistle.

What's particularly interesting about rutting deer is that the chosen behaviour can vary with habitat. Fallow, for example, may adopt a more harem-based rutting plan in open habitats, and clashes - where two males lock antlers, each trying to push the other back - are more common in open areas than in woodland. Presumably, open habitat allows the deer to see rivals and might make them more prone to fight than in woodland where they can generally only hear them.

Japanese sika deer stags clashing in the New Forest. The rut is a dangerous time males as they compete for access to females - injuries (sometimes even deaths) are not uncommon during the autumn rut. Here you can see the steam rising from these guys as they relentlessly shove each other back and forth. - Credit: Marc Baldwin

The deer rut is fascinating and very entertaining to watch, but please remember that, even in deer parks like Richmond, Bushy and Petworth, getting too close can both disturb the deer and be dangerous for you—these are large mammals pumped up on testosterone, and this makes them unpredictable. Please keep your distance and don't risk your safety, or theirs, for the sake of a photo. If you want to watch the rut this autumn, there are several parks and gardens that hold managed populations of free-ranging deer across the UK—check out the British Deer Society's website to find one local to you. The Deer Society also have a Code of Conduct pertaining to photographing deer.

If you're wondering, incidentally, about the species missing from the above account: roe deer rut during late July and early August, Chinese water deer in December, and Reeves' muntjac can breed throughout the year, although in my experience (i.e., based on what I have observed recently-born fawns) they tend to rut during the early winter and mid-summer.

For a round-up of Britain's seasonal wildlife highlights for October, check out my Wildlife Watching - October blog. As pannage season starts this month, a reminder that you can also find out everything you ever wanted to know about the ancient tradition in my pigging out on the forest blog.

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