Spring has been quite remarkable in the UK – long, hot, sunny spells throughout May for most of the country, particularly in the east. Indeed, according to the BBC, spring 2025 outshone the whole of last summer. The prolonged high pressure finally broke as we headed into the final weekend of last month, with a large, slow moving area of low pressure bringing significant rain the likes of which we'd not seen for more than a month, much to the delight of farmers and gardeners. As we exit May and enter June, the models conflict over whether it will remain cool and unsettled or high pressure will build back in and send temperatures climbing.
Speed Read of the Month
Not a new species this month, but instead a complete overhaul of one of the old Speed Reads. The Mountain hare Speed Read has thus been reviewed and updated to provide a more comprehensive overview of the species.
Website news
A few minor updates have been made to the red fox article, specifically the parasite and disease sections. Additionally, the next section of the Chinese water deer article went online at the end of last month, this one covering the hunting of the species and its response to human disturbance.
News and discoveries
Roe-ing season. The roe deer (Capreolus capreolus) is Europe's most widely distributed ungulate and one of only two deer species native to Britain, the other being the red deer (Cervus elaphus). The roe deer is unique among cervids in its ability to conceive during the summer and pause embryonic development over the winter, resuming it in the spring so the kids can be born when food and cover are plentiful. Shifts in birth dates in recent decades have stimulated debate as to the control of mechanisms regulating diapause, but a new study from Germany has shed light on this phenomenon. Johanna Kauffert and colleagues studied embryos from 390 roe deer shot by stalkers in Bavaria between 2017 and 2020 to identify the date of diapause. The results, published in the Proceedings of the Royal Society last month, suggest that high-quality, well-conditioned and prime aged females (2-6 years old) terminate embryonic diapause earlier than senescing females, and that the growing season length in the year of conception significantly influences the diapause timing. The longer the growing season in the year of conception, the earlier the females terminated diapause.
Of bovines and badgers. The debate around the role that badgers (Meles meles) play in the transmission of bovine tuberculosis to cattle continues to rage as the government talks about ending culling and the promotion of a vaccine strategy. A big part of any attempt to manage a disease that has a wildlife reservoir involves understanding how the associated species interact, and this is particularly so with badgers that have a long history of living on and using farmland. A new study, published in Ecology and Evolution recently, builds on our previous knowledge in this arena, presenting data from 35 GPS collared badgers in 446 fields across 18 farms between May and November 2016. The data show badgers entered fields grazed by cattle on about 20% of nights, with the same badgers frequently found in the same fields on multiple occasions, although about one-third of the badgers never associated with cattle. Interestingly, badgers were much less likely to be found in fields where calves were present but were attracted to fields with fodder and rough grazing. The researchers suggest that: "Delaying grazing of fodder fields after (silage) harvest until sward length has increased, restricting grazing to improved pastures, keeping calves with cows longer, or ensuring all batches of cattle have at least some calves present and not grazing fields with badger setts (or fencing around setts to prevent cattle access) may provide simple, cost-effective strategies to reduce indirect badger–cattle contact, thus potentially lowering bTB transmission risk."
Hedgehog highways. The global decline in biodiversity has proceeded for more than a century, but the decline has become more accelerated since the 1940s. Here in Britain, one species that has seen a precipitous decline over this time has been the hedgehog (Erinaceus europaeus), numbers falling in response to a myriad of factors, some of which are poorly understood. We do know, however, that habitat loss and fragmentation are significant contributing factors. A long-standing assumption has been that disparate hedgehog populations are isolated/fragmented and that this inhibits gene flow, thereby making them vulnerable to extinction. A new genetic study of hedgehogs across a nearly 6,000 sq-km (2,300 sq-mi) area of South Wales has suggested hedgehog may be more mobile that we once assumed. DNA samples taken from nearly 300 hedgehogs brought into the Gower Bird Hospital between October 2019 and September 2021 showed only weak genetic structuring of hog populations across this large area, but indicated that the overall population was well admixed, suggesting that hedgehogs are able to disperse across roads and waterways that were expected barriers in their landscape.
Best behaviour? While scientists have historically been reluctant to recognise personality traits in animals, anyone who has lived or worked with other species is quick to point out how it's not only humans who show individual traits. Growing up, all our companions exhibited different personalities. In recent decades, we've begun to understand more about how the personality of animals helps them adapt to different environments, how urban individuals are often forced to be more social than rural ones, for example, but new research from the University of Michigan suggests personality trails can trickle down to into the wider landscape. Over two years, the scientists tracked the way 50 grey squirrels (Sciurus carolinensis) of known personality interacted with more than 3,200 seeds that they put out in nearly 140 feeding stations. Their data, published in Global Ecology and Conservation, reveal that more social individuals were more likely to consume novel seeds (i.e., those that aren't found in the local area) than native ones when the seeds were removed from the stations. This could plausibly inhibit the spread of new species of tree into the area, while promoting dispersal of native trees. Furthermore, the researchers observed the squirrels taking seeds through urban areas, potentially helping some tree species disperse even in the face of increasing urbanization. The biologists conclude: "Overall, individuals contributed to novel seed dispersal differently based on personality, highlighting the need to preserve behavioral diversity to facilitate tree range shifts."
For a round-up of Britain's seasonal wildlife highlights for early summer, check out my Wildlife Watching - June blog.