August ended on an unseasonably wet and windy note after a couple of deep low pressure systems (storms “Ellie” and “Francis”) passed over. The start of September was similarly dominated by low pressure, the first week starting chilly and dry then turning wet and windy, with thundery showers in the north and temperatures just below the seasonal average.
The second week got off to a cloudy, gloomy and blustery start, particularly in Scotland, which saw some heavy rain and gale-force winds. Across the south, milder Atlantic air filled in and we saw temperatures rise into the low 20s Celsius (~70F) with some accompanying humidity.
The second weekend of September brought wet weather to the north - a month's worth of rain over the hills of western Scotland in a couple of days. Further south, we started dry and cloudy with temperatures continuing to rise into the third week courtesy of a “plume” of warm air, with temperatures hitting 31C (88F) on Jersey and in the south-east during the first few days. Temperatures remained high into the middle of the fourth week before we saw low pressure systems arrive from the west, bringing some wet and windy weather. Temperatures in the fourth week here on the south coast dropped from highs of 25C to 12C (77-54F) overnight, with some much-needed rain accompanied by gusty winds. The last week or so of September remained cooler and unsettled, which was good news for the New Forest deer as the rut got underway. Northern Ireland recorded its coldest September night on record on 26th/27th; -3.7C (25F) in the County Down hamlet of Katesbridge.
The last weekend was windy across the country with East Anglia seeing the strongest winds and heaviest rain. This cleared for most over the latter part of Sunday, although Scotland saw heavy rain to start the last week. After a couple of days of settled and drier weather, with temperatures back to around the average for the time of year, the jet stream began to, as one BBC forecaster put it, “wake up” on the last day of the month. A deep low just south of Iceland brought strong winds and heavy rain to see out the first month of autumn.
If you’re interested in the wildlife to be found this month, including the peak of the red, fallow and sika deer rut, the ‘shrewicide’ season and the best time to watch salmon migrating upstream to their spawning grounds, check out my Wildlife Watching - October page. October is the middle of the Common of Mast, or pannage season, with the pigs out on the New Forest hoovering up acorns and other mast.
Some minor updates have been made to the fox senses article and a summary of the ‘antlers are cancers’ theory has been added to the deer antler QA. Additionally, new SpeedReads have been added covering the wood mouse, bank vole and otter, with dormouse and wildcat editions planned. The research for a new article on the Chinese water deer is also underway.
In the news
A few headlines making the conservation news this month include the drivers for large-scale deer movement and some good and bad news about human’s impact on the planet:
- Sharing food aids monkey business. New research from the University of St Andrews suggests that the sharing of food by monkeys could be the equivalent of humans going out on a dinner date. For the first time, scientists have recorded six events of food transfer by wild golden lion tamarin adults in different groups, suggesting these small simians may have a more complex and flexible social life than we previously thought. It also posits that food transfer may help create and strengthen social relationships outside the family group.
- Plant power drives deer migration. New data from a huge GPS tracking study of nearly 1,700 deer, combined with satellite vegetation analysis by researchers at the University of Wyoming, has found that changes in vegetation flush drives migration in four species of deer. Shortened migrations or increased residency, by contrast, appear to have been caused by food subsidies such as agriculture and supplemental feeding. These data allow scientists to better understand the types of landscapes in which ungulates need to migrate and where conservation corridors can have maximum effect.
- Unprecedented human impact on earth. Over the past few years we’ve seen a number of stories about the negative impact that humans are having on the earth’s ecosystems, from plastic in our oceans to wet markets being the perfect breeding grounds for new zoonotic pathogens. Last month, the Zoological Society of London and WWF published their biennial Living Planet Report, which makes even grimmer reading. It shows wildlife populations in what can only be described as “freefall”, having declined by an average of almost 70% since the 1970s.
- Animal extinction rates reduced by conservation projects. Off the back of the Living Planet Report, the results of a new study in press with the journal Conservation Letters provide a glimmer of hope when it comes to saving species from extinction. The multidisciplinary team presented data suggesting that nearly 50 species (including Iberian lynx, Przewalski wild horses and hairy-nosed wombat) have been saved from extinction by conservation projects, and the extinction rate for birds and mammals would’ve been up to four times higher without action.
- Going batty over Coronavirus? With early speculation that the CV-19 virus originated in bats, there has been a great deal of msinformation and many unfounded statements involving bats circulating online. In response, Ecology by Design have created a free online quiz to help educate people about the important role bats play in Earth's ecosystems.
Discoveries of the Month
Moles out on the town
The bane of many a gardener and greenskeeper, the mole has a somewhat controversial place among Britain’s mammal fauna. Evidence of their endeavours, the familiar spoil heaps we refer to as molehills, are a source of good quality soil that many gardeners use for potting plants, but they are unsightly to many and present potential danger to livestock. Indeed, an entire “pest control” industry has grown around some peoples’ disdain for these animals - but moles are vital ecosystem engineers, promoting soil mixing, eating a number of insect “pests” and even helping promote water vole colonisation in some habitats.
Moles may be a familiar feature of our countryside and rural gardens, but we know very little about how they respond to urban development.
The number of new homes registered to be built annually in Britain has risen by more than 80% over the last decade, and the UK government has a target of building 300,000 new homes each year. This rapid increase in development has significant consequences for a huge range of species, with moles being particularly vulnerable as fields are tarmacked over.
A new study by a team of British and Brazilian scientists provides insight into how moles respond to urbanisation, and it’s not as bad as we feared. The researchers, led by Mark Fellowes at the University of Reading, surveyed a 90 sq-km (35 sq-mi.) area of Reading for signs of mole activity over 74 days between April and July 2018. Some 650 mole territories were mapped across the area and the moles were surprisingly widespread in urban, suburban and periurban greenspaces.
A particularly reassuring finding of the study was that the degree of urbanisation (i.e. how many constructed surfaces there were within 150m/492 ft. of the green space) didn’t appear to affect the presence of moles. Quite the contrary, in fact. Surprisingly, the highest mole densities were found at sites with more peripheral development.
The data also suggest that, while urbanisation is tolerated, moles require green spaces of about 10ha (25 acres) to persist. Writing in the journal Animals in June, Fellowes and his colleagues also caution that some planning mitigation may still be required to reduce greenspace fragmentation:
“Being subterranean, moles are perhaps less influenced by factors such a human disturbance, but they will be sensitive to land management strategies, especially those, such as fragmentation by roads and development, that will influence the ability of juveniles to disperse.”
Source: Fellowes, M.D.E. et al. (2020). Map-A-Mole: Greenspace Area Influences the Presence and Abundance of the European Mole Talpa europaea in Urban Habitats. Animals. 10: 1097. doi:10.3390/ani10061097
Putting out food for hedgehogs affects their activity patterns
A great many of us gain pleasure from feeding the wildlife that visits our gardens. Birds are among the most likely to receive this “supplementary feeding” - a recent survey by the British Trust for Ornithology estimated that three-quarters of British households feed the birds at some point during the year, and the bird food industry is worth in the region of £200 million (€219m / US$256m) to the UK economy annually. Avians aren’t the only focus, however, with many of us laying on provisions for our mammalian visitors, too.
One significant concern when it comes to putting food out is whether you’re affecting the animals’ natural behaviour and, perhaps, making them dependent on the food. While evidence that providing food for garden wildlife leads to dependency or an inability to find food for themselves is sketchy at best, we are now starting to see that supplementary feeding can result in the animals changing their activity patterns to visit certain gardens first, more regularly, and often for longer. A new study by Abigail Gazzard and Phil Baker at the University of Reading in Berkshire suggests even our innocuous Tiggywinkle is not immune to the draw of a handout.
The researchers recruited volunteers from 63 households across Reading to survey for hedgehog presence/abundance in their gardens between November 2017 and April 2018. The surveys found that hedgehogs were significantly more likely to be found in gardens where householders put food out for them than in those where food was not offered – 84% and 34%, respectively. Winter occupancy showed the same trend, with 64% found nesting in gardens where they were fed versus 8% in gardens where supplementary food wasn’t provided. Writing in the journal Animals, Gazzard and Baker suggest:
“As a result, hedgehogs could be getting “mixed messages”, that is, food availability is still high even though temperatures are low. Ultimately, this could result in maladaptive responses leading to reduced over-winter survival rates and longevity.”
At the same time, however, the authors concede that supplementary feeding could be an important means for underweight hedgehogs to put on sufficient weight to overwinter, and provides a valuable snack for hedgehogs rousing from hibernation. Indeed, a recent study of hedgehogs hibernating in a Cornish rescue centre suggested that larger hedgehogs lost less weight over hibernation because they fed when they aroused from hibernation. It is perhaps notable that even in the rescue centre, where food is provided ad libitum, hedgehogs still underwent hibernation, and this has been the experience of a number of hedgehog careers.
In addition to the foregoing, I would challenge the notion that hedgehogs hibernating for shorter periods, or even failing to hibernate altogether in urban environments, is intrinsically problematic. Hibernation is a dangerous event and one that hedgehogs undertake out of necessity as temperatures drop and their food supply dries up. Not hibernating is unlikely to prove detrimental, provided food is supplied throughout the winter, although it does potentially expose the animals to year-round mortality from predators or cars. Of course, they are likely to be significantly less active if temperatures remain low given how poorly insulated they are.
So, these new data provide an interesting insight into how feeding hedgehogs can alter their choice of which gardens to visit, when, and even where they overwinter. What we don’t yet fully understand is whether this is a problem for hedgehogs. Is this any worse than, for example, encouraging hedgehogs by installing log piles and ditching pesticides? In short, if you put food out for hedgehogs, don’t stop yet, but do make sure you’re providing suitable food for them - avoiding peanuts, mealworms, sunflower hearts, bread and milk - and keep it up into the winter.
Source: Gazzard, A. & Baker, P.J. (2020). Patterns of feeding by householders affect activity of hedgehogs (Erinaceus europaeus) during the hibernation period. Animals. 10: 1344. doi:10.3390/ani1008134