One evening on Holt Heath in Dorset over 40 years ago has been branded permanently in my memory.
In the twilight, first the ‘churring’ sounds started, almost like a distant intermittent motorbike. Then, as we waited with bated breath under the few Scots pines among the heathland, a slow, soft clapping could be discerned. Then the full reveal: a couple of nightjars, with their ghostly courtship display as they fluttered between the trees, flapping their wings almost like butterflies, tenderly but with intent, interspersed with more churring. Magical!
Nightjars are one of our most intriguing summer visitors, arriving April to May and leaving in August. Their name, Caprimulgus europeaus, reflects their ancient common name – ‘goatsucker’, as it was thought that they sucked the milk from young goats. Actually they were probably found around livestock due to the insects that were stirred up. Although their range declined by more than half in the UK between 1972 and 1992, they are now increasing somewhat due to greater availability of young pine plantations. However, their heathland habitat is still threatened and they are prone to disturbance by dogs off leads and people walking off paths. Their distinctive churring call of 1900 notes a minute makes up for their very cryptic colouration, and they will be most easily spotted by call in the hour after dusk when, as well as conducting their courtship, they are hunting for insects. If there is a full moon in early June, many nightjars will start nesting on that date, so that when the moon is next full, the conditions will be at their best for catching moths for their growing young.
Bats can also be best seen flying around dusk, the commonest and smallest bat in the UK being the pipistrelle, often seen in our gardens or flitting around lamp posts. It is small enough to fit in a match box and weighs about the same as 10 paper clips! In summer, pipistrelles roost in tree holes, bat boxes and even the roof spaces of houses. In June and July they give birth to one baby, called a pup, and catch around 3,000 insects per night to feed it. Three or four weeks later the young bats are able to fly and they leave the roost in August.
One reason that bats and nightjars are active around dusk is because a large part of their diet, moths, are active then. There are a few day-flying moths, but the majority of the UK’s around 2,500 species of large moth are nocturnal, including the extraordinary elephant hawk moth. Who said moths were dull! This moth gets its name from the large caterpillars which are supposed to resemble an elephant’s trunk, but the adults are also pretty spectacular. They are found throughout England and Wales. They fly at dusk and can be attracted to lights, so we have been delighted to find them in the moth traps we run at my school. In the day they may rest among the tubular flowers that they feed from, such as honeysuckle. The caterpillars feed on wasteland plants such as rosebay willowherb, bedstraw and that well known invasive plant, Himalayan balsam.
My final dusk-loving species – the glow worm, is not so common, and not easily spotted with current levels of light pollution, so we were delighted to find some in our relatively dark school back gardens. It is actually not a worm at all, but a 20- 25mm long beetle. Its Latin name – Lampyris noctiluca – means “night lantern-bearer”. It is only the female adults that produce continuous bioluminescence from the last 2 segments of the abdomen, to attract males for mating. The female has an adult glowing life of only a few weeks in June until she mates, as she dies soon after laying her eggs. After the larvae hatch out it takes 2 or 3 summers before they become adults. During that time they feed on small snails which they paralyse before sucking them empty. The long gap between mating and the appearance of the next generation adults helps explain why glow worms may be found one year in a location and then not the next year.
Want to find out more? Click through to the following websites for further information:
–Glow worms: https://www.glowworms.org.uk/
This blog was written by Ann Stuart for the ‘Nature and worship’ Wild Christian email. Ann is an A Rocha UK Board member and former Biology teacher at Monkton Combe School.
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