Just like March, April started on a warm and sunny note for much of Britain, with temperatures reaching 23C (73F) in the south during the first week, remarkably balmy for early April. This long spell of spring sunshine was the result of what meteorologists call "Omega Blocking"; a similar high-pressure pattern keeping Atlantic fronts away (i.e., "blocking" them) was responsible for the long, hot summer of 1976. Unfortunately, contrary to popular misconception, while high pressure systems generally mean dry weather, it doesn't always mean sunny conditions, and we can end up with day on end of so-called anticyclonic gloom. In the south, at least, we nonetheless ended the month with some clear blue skies and temperatures well above average.
Speed Read of the Month
This month we take a whistle-stop tour of the natural history of the most widely distributed reptile in the world, with a new Speed Read on the common (or viviparous) lizard. This short-legged lizard is found throughout Britain and Ireland, barring the Canaries and some Scottish islands, although concerns have been raised recently that numbers are declining in England.
News and discoveries
Summer smells. Britain has lost 97% of its wildflower meadows since the 1930s, which is one of many reasons why our pollinators are declining. Of the 270 or so bee species in the UK, 35 are at risk of extinction, despite their pollination activities being worth an estimated £2 billion per year to Britain's farmers. While honeybees are quite abundant, owing largely to private keeping interests, they are often not as efficient at pollination as some of the solitary species in decline. According to Friends of the Earth, for example, red mason bees are 120 times more efficient at pollinating apple trees than honeybees. Quite how climate change is impacting bees is a matter of some debate, but a recent study by researchers at the University of Würzburg in Germany suggests rising temperatures affect the sense of smell of bumblebees. The research, published in Proceedings of the Royal Society, involved monitoring 190 bees from two species common in Europe (Bombus pascuorum and Bombus terrestris) and that when the bees were exposed to temperatures of 40C (104F) for three hours, the heat exposure reduced the bees' antennal response to various floral scents by up to 80%. This suggests a sharp decline in their ability to detect these floral signals and, ultimately, to find food. The desensitisation was long-lasting, wild individuals were more susceptible than commercially bred ones, and workers were the most susceptible cohort.
Pachyderm protection. Elephants are a conservation conundrum. They're a threatened species that need our conservation, but they are also a significant source of crop damage in Africa. In Tanzania alone, in 2009, elephants were calculated to have destroyed just over 15,000 ha (37,000 acres) of crops. Farmers and conservation bodies alike are always looking for ways to keep elephants and farms apart, and now a combination of Artificial Intelligence (AI) and thermal imaging is showing promise. A system called Human Elephant Alert Technologies (HEAT) has been developed in combination with the Zoological Society of London and uses AI software to identify elephants by their thermal image, having been trained on some 20,000 images of the elephants housed at Whipsnade in Bedfordshire. The HEAT system is about to undergo a trial in Thailand's Western Forest Complex, and the aim is for the system to alert rangers to approaching elephants in time for them to be mobilised and intercept these giants before they reach the farms.
Residential Reynard. Foxes living in our towns and cities are a common sight these days across many parts of Europe, Asia and North America. Indeed, some survey data suggests that, in Britain at least, fox populations are larger in towns and cities than in the countryside where they face significant persecution. One question that's often asked is whether urban foxes are different from those living in the countryside. Many countrymen will tell you the urban fox is a meagre beast unable to survive in the wilds of the countryside, but the data we have really doesn't support that, and tracking data show foxes moving between town and country, sometimes on a nightly basis. Recent data from Poland suggest, however, that we are starting to see a differentiation in some populations. In their paper to the Journal of Zoology published in February, Mateusz Jackowiak and colleagues at the Institute of Environmental Protection in Warsaw report on the reproduction variation between foxes living in Warsaw city centre and those in a forest-field mosaic in Central Poland. The results suggest that urban animals bred, on average, two weeks earlier than rural ones and had slightly larger litters (i.e., up to 7 cubs were reported among the 56 city litters assessed, while 6 cubs was the largest litter among the 130 rural litters) and were more likely to live in small social groups, while rural animals were only ever found in pairs. These findings illustrate how profitable urban areas can be for species willing to cohabit with humans.
Brilliant beavers. Familiar to many of us as the accommodating animals who take in Peter, Susan, Edmund, and Lucy Pevensie in C.S. Lewis' timeless classic The Lion, the Witch and the Wardrobe, published in 1950, the beaver was once a common and widespread animal in Britain. Centuries of persecution for fur, castoreum, and meat, combined with competition with farmers for land, resulted in the beaver's extinction throughout Britain and much of Europe. When beavers disappeared, so too did a host of ecosystem services that we're only now starting to recognise. While we know a reasonable amount about how beaver dams can help reduce flooding, clean water courses, boost fish populations, and so forth, less is known about the impact of their lodges. In a recent paper to Mammal Review, Jude Wilson and Samantha Bremner-Harrison present a detailed literature review suggesting beaver lodges act as biodiversity hotspots, significantly richer in species than surrounding microhabitats. Overall, 86 species were recorded interacting with beaver lodges, including 28 mammals, 33 birds, at least three reptile and five amphibian species, five fish species, and 12 macroinvertebrate families.
For a round-up of Britain's seasonal wildlife highlights for late spring, check out my Wildlife Watching - May blog.